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Adelar Bracht - One of the best experts on this subject based on the ideXlab platform.
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transport Distribution Space and intracellular concentration of the anti inflammatory drug niflumic acid in the perfused rat liver
Biochemical Pharmacology, 1993Co-Authors: Ana Maria Kelmerbracht, Emy Luiza Ishiiiwamoto, Adelar BrachtAbstract:Abstract Transport and Distribution Space of niflumic acid in the perfused rat liver were investigated employing the multiple-indicator dilution technique with constant infusion of the drug (step input). Niflumic acid permeated the cell membrane in both directions at very high rates and its Distribution in the cellular Space was flow-limited; at least at 37°, the rates of influx and efflux could not be measured. Dissociation of the niflumic acid-albumin complex also occurred at very high rates. The apparent Space of Distribution of niflumic acid in the liver depended on the concentration of the drug and varied between 4.37 (1 mM) and 43.5 (10 μM) times the water Space; even with 90% extracellular binding to albumin, the apparent Space of Distribution of niflumic acid was 5.1 times greater than the water Space. The high apparent Spaces of Distribution reflected the high intracellular concentrations. The ratio of intracellular bound plus free concentration to the extracellular bound plus free concentration ( C i / C e ) varied between 6.62 (1 mM portal niflumic acid) and 71.0 (10 μM portal niflumic acid). Metabolic transformation depended on the concentration of the free form. Intracellular binding is probably the major reason for the high concentration of the drug in the hepatic tissue.
Donald Armstrong - One of the best experts on this subject based on the ideXlab platform.
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The arabinitol appearance rate in laboratory animals and humans: estimation from the arabinitol/creatine ratio and relevance to the diagnosis of candidiasis. J Infect Dis
2016Co-Authors: B Wong, Edward M. Bernard, Jonathan W. M. Gold, Danny Fong, Donald ArmstrongAbstract:The effects of renal function on serum concentrations of the candidal metabolite ara-binitol were studied by examining the accumulation and elimination of arabinitol in ani-mals and humans. Serum concentrations of arabinitol rose sharply and in direct propor-tion to creatinine concentrations after nephrectomy in rats. The serum half-life of ex-ogenous arabinitol was 20.8 hr in anephric rats but only 0.62 hr in sham-nephrectomized control animals. The mean ± SD apparent Space of Distribution of arabinitol was 419 ± 26 mllkg. The fraction of exogenously administered arabinitol recovered in the urine was 0.73 ± 0.13 in uremic rats, 0.85 ± 0.28 in control rats, and 0.95 ± 0.10 in normal dogs. The arabinitollcreatinine clearance ratio was 0.99 ± 0.08 in normal dogs and 0.99 ± 0.25 in 22 critically ill patients with cancer. Thus arabinitol is eliminated by nearly quantitative urinary excretion and is cleared at virtually the same rate as creatinine. Therefore, the rate of arabinitol appearance in the body from any source equals the urinary arabinitol excretion rate and is directly proportional to the concentration ratio of arabinitol to creatinine in serum or urine. Large amounts of arabinitol are produced in vitro by Candida albicans, Candida tropicalis, and Candida parapsilosis, the species responsible for most cases of human candidiasis [1]. We and other investigators have found high serum concentra-tions of arabinitol in patients with invasive candi-diasis [2-6] but also in uninfected patients with renal failure [2, 3, 6, 7]. In an earlier study, we es-timated that the normal serum arabinitol concen-tration was up to 1.0 J.tg/ml if the serum creatinine Received for publication December 14, 1981, and in revise
Davide La Torre - One of the best experts on this subject based on the ideXlab platform.
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approximating Distribution functions by iterated function systems
Journal of Applied Mathematics and Decision Sciences, 2005Co-Authors: Stefano Maria Iacus, Davide La TorreAbstract:An iterated function system (IFS) on the Space of Distribution functions is built with the aim of proposing a new class of Distribution function estimators. One IFS estimator and its asymptotic properties are studied in detail. We also propose a density estimator derived from the IFS Distribution function estimator by using Fourier analysis. Relative efficiencies of both estimators, for small and moderate sample sizes, are presented via Monte Carlo analysis.
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approximating Distribution functions by iterated function systems
2002Co-Authors: Stefano Maria Iacus, Davide La TorreAbstract:In this small note an iterated function system on the Space of Distribution functions isbuilt. The inverse problem is introduced and studied by convex optimization problems. Applicationsof this method to approximation of Distribution functions and estimation are presented.
Ana Maria Kelmerbracht - One of the best experts on this subject based on the ideXlab platform.
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transport Distribution Space and intracellular concentration of the anti inflammatory drug niflumic acid in the perfused rat liver
Biochemical Pharmacology, 1993Co-Authors: Ana Maria Kelmerbracht, Emy Luiza Ishiiiwamoto, Adelar BrachtAbstract:Abstract Transport and Distribution Space of niflumic acid in the perfused rat liver were investigated employing the multiple-indicator dilution technique with constant infusion of the drug (step input). Niflumic acid permeated the cell membrane in both directions at very high rates and its Distribution in the cellular Space was flow-limited; at least at 37°, the rates of influx and efflux could not be measured. Dissociation of the niflumic acid-albumin complex also occurred at very high rates. The apparent Space of Distribution of niflumic acid in the liver depended on the concentration of the drug and varied between 4.37 (1 mM) and 43.5 (10 μM) times the water Space; even with 90% extracellular binding to albumin, the apparent Space of Distribution of niflumic acid was 5.1 times greater than the water Space. The high apparent Spaces of Distribution reflected the high intracellular concentrations. The ratio of intracellular bound plus free concentration to the extracellular bound plus free concentration ( C i / C e ) varied between 6.62 (1 mM portal niflumic acid) and 71.0 (10 μM portal niflumic acid). Metabolic transformation depended on the concentration of the free form. Intracellular binding is probably the major reason for the high concentration of the drug in the hepatic tissue.
B Wong - One of the best experts on this subject based on the ideXlab platform.
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The arabinitol appearance rate in laboratory animals and humans: estimation from the arabinitol/creatine ratio and relevance to the diagnosis of candidiasis. J Infect Dis
2016Co-Authors: B Wong, Edward M. Bernard, Jonathan W. M. Gold, Danny Fong, Donald ArmstrongAbstract:The effects of renal function on serum concentrations of the candidal metabolite ara-binitol were studied by examining the accumulation and elimination of arabinitol in ani-mals and humans. Serum concentrations of arabinitol rose sharply and in direct propor-tion to creatinine concentrations after nephrectomy in rats. The serum half-life of ex-ogenous arabinitol was 20.8 hr in anephric rats but only 0.62 hr in sham-nephrectomized control animals. The mean ± SD apparent Space of Distribution of arabinitol was 419 ± 26 mllkg. The fraction of exogenously administered arabinitol recovered in the urine was 0.73 ± 0.13 in uremic rats, 0.85 ± 0.28 in control rats, and 0.95 ± 0.10 in normal dogs. The arabinitollcreatinine clearance ratio was 0.99 ± 0.08 in normal dogs and 0.99 ± 0.25 in 22 critically ill patients with cancer. Thus arabinitol is eliminated by nearly quantitative urinary excretion and is cleared at virtually the same rate as creatinine. Therefore, the rate of arabinitol appearance in the body from any source equals the urinary arabinitol excretion rate and is directly proportional to the concentration ratio of arabinitol to creatinine in serum or urine. Large amounts of arabinitol are produced in vitro by Candida albicans, Candida tropicalis, and Candida parapsilosis, the species responsible for most cases of human candidiasis [1]. We and other investigators have found high serum concentra-tions of arabinitol in patients with invasive candi-diasis [2-6] but also in uninfected patients with renal failure [2, 3, 6, 7]. In an earlier study, we es-timated that the normal serum arabinitol concen-tration was up to 1.0 J.tg/ml if the serum creatinine Received for publication December 14, 1981, and in revise