Effect Of Albumin Concentration Research Articles

Foam mat drying of coffee aqueous extract: Foam process optimization, drying kinetics, energy consumption, and energy efficiency analysis

The instant coffee consumption has been growing mainly due to consumer's search for quick-prep foods. Foam mat drying (FMD) is an innovative technique that promises energy savings for industries. The instant coffee production by FMD was evaluated by identifying the best foaming conditions and analyzing the kinetics and energy aspects of drying. The effect of albumin concentration (3.5–6.5 % w/V), whipping time (2.5–12.5 min) and stand mixer rotation speed (975.67–1066.67 rpm) on properties of foamed coffee extract (FCE) was investigated using a desirability function. FCE at optimal condition (5.05% w/V, 6.5 min and 1066.67 rpm) was dried in oven (50–90 °C). Increasing the drying air temperature reduced the process time due to the increase in the drying rate and resulted in reductions in specific energy consumption and CO2 emissions. Energy efficiency was reduced over time. These results show that FMD is a promising technique to produce instant coffee.

The relationship between plasma albumin, alkaline phosphatase and pyridoxal phosphate concentrations in plasma and red cells: Implications for assessing vitamin B6 status.

Plasma concentrations of most vitamins decrease as part of the systemic inflammatory response (SIR). Thus low plasma values do not necessarily indicate deficiency. Vitamin B6 status is usually assessed by measurement of pyridoxal phosphate (PLP) in plasma, although vitamin concentrations in blood cells tend to be better markers of cellular stores. In health, plasma PLP appears to be determined primarily by intake, its binding to albumin, and its hydrolysis by alkaline phosphatase (ALP). To examine, using invitro studies, the effect of albumin concentration and ALP activity on PLP concentration in plasma and red blood cells of healthy subjects (HS) and critically ill patients (CI). Heparin and EDTA (ALP inhibited) whole blood samples from HS (n=8) and CI (n=26) were incubated with PLP. Concentration of PLP in plasma and red cells was measured. Albumin and ALP levels were determined in plasma. In PLP incubated heparin samples, there was a strong direct relationship between albumin in the concentration range 10-44g/L and increase in plasma PLP concentration (rs=0.93, P<0.001) and an inverse relationship with increase in red cell PLP concentration (rs=-0.90, P<0.001). In contrast, ALP activity was inversely associated with increase in plasma PLP concentration (rs=-0.42; P=0.013) and directly associated with red cell PLP concentration (rs=0.49; P=0.003). Plasma albumin concentration and to a lesser extent ALP activity influences PLP concentration in plasma and red cells. In conditions associated with low albumin (e.g. SIR) or altered ALP activity, red cell PLP measurements are more likely to be reliable than plasma measurements in differentiating true from apparent vitamin B6 deficiency and to guide vitamin B6 supplementation.

In vitro conditions for performance evaluation of products for intravascular administration: Developing appropriate test media using Amphotericin B as a model drug

Currently, there are no compendial in vitro release tests specifically indicated for parenteral formulations. Consideration of biorelevant and clinically relevant test media represents a valuable approach for the development of in vitro tests that ideally can provide information on the formulation performance in vivo. The aim of this study was to investigate the effect of different media components on the solubility of Amphotericin B (a poorly soluble highly protein-bound drug) in order to develop biorelevant and clinically relevant media for future in vitro release testing from its liposomal formulation. Three categories of media were considered in the development approach: Category 1 media: effect of albumin concentration; category 2 media: effect of biorelevant concentrations of plasma components (bile salts, phospholipids, cholesterol, albumin); category 3 media: attaining clinically relevant solubility with biorelevant and synthetic surfactants with and without albumin and setting the basis for the development of a simulated hypoalbuminaemic plasma medium. All the surfactants tested increased Amphotericin B solubility while the simultaneous presence of albumin had a negative effect on solubility. Clinically relevant media with the use of biorelevant or synthetic surfactants and albumin were developed. One medium in which the solubility of Amphotericin B was reduced was identified as potential candidate medium to simulate hypoalbuminaemic plasma. The development of biorelevant and clinically relevant media and understanding the effect of media components and their interactions, supports future development of meaningful in vivo predictive release tests for parenteral formulations.

Apparent clearance of valproic acid in elderly epileptic patients: estimation of the confounding effect of albumin concentration

Background. Valproic acid (VPA) apparent clearance (CL) estimated from total serum concentrations is analogous in elderly and non-elderly adult patients. As drug–protein binding decreases in old age, the aim of our study was to evaluate the confounding effect of the serum albumin concentration on the VPA apparent CL in elderly patients.Methods. In 102 epileptic out-patients treated with VPA in monotherapy, serum total steady-state trough concentrations (Css) were determined. Css concentrations were normalized for a 42 g/L albumin concentration (CssN), and the apparent CL and normalized apparent CLN were calculated.Results. A poor concordance of 53% was found in the classification of Css and CssN levels of VPA as subtherapeutic, therapeutic, or supratherapeutic dose. In the elderly (≥65 years) and non-elderly adult patients, the VPA apparent CL was similar; however, normalized apparent CLN was significantly lower in older patients (P < 0.01), with a 40% median decrease.Conclusions. Total VPA concentrations should be interpreted with caution, mainly in older patients, in which determination of unbound or normalized total drug concentrations may be clinically useful. Normalization of total concentrations permits an estimation of the masking effect of serum albumin concentrations on the VPA apparent CL in elderly patients.

Effect of albumin concentration on serum cortisol measured by the Bayer Advia Centaur assay

A poor comparison was seen between the Bayer Advia Centaur and the Roche Elecsys cortisol methods using samples sent to the laboratory for cortisol analysis. They were predominantly from patients attending the Endocrine outpatients clinic or patients in the intensive therapy unit. We investigated the effect of albumin concentration on the performance of both assays. For the samples used in the patient comparison, the laboratory database was searched for any concomitant albumin concentrations (Beckman LX20 BCP method). A series of recovery experiments were performed combining samples with normal albumin and undetectable cortisol concentrations with samples with detectable cortisol but low albumin concentrations. Albumin concentration accounts for almost 50% of the variation in the difference between the two methods. The Bayer Advia Centaur method shows significant under-recovery at albumin concentrations lower than 24 g/L. This under-recovery will significantly affect the diagnosis of adrenal insufficiency in critically ill patients with low albumin concentrations.

Effect of Concentration and Hyaluronidase on Albumin Diffusion Across Rabbit Mesentery

To measure the diffusion coefficient of albumin through rabbit mesentery using the steady-state flux of radioactive tracer 125I-albumin. The effect of albumin concentration and testicular hyaluronidase were also studied. Mesenteric tissue was bonded between two plates, exposing a 7 mm diameter surface, with two chambers on either side. One chamber was filled with a test solution of albumin containing the radioactive tracer and the other with lactated Ringer solution. The solutions in both chambers were stirred with small magnetic cylinders. The chamber filled with lactated Ringer solution was placed in a well-type NaI(Tl) detector, and the radiation emitted from the tracer that diffused across the mesentery was monitored continuously for 9 hours. The diffusion coefficient (D) was calculated using Fick's law of diffusion. The diffusion coefficient was measured at albumin concentration differences (delta C) between approximately 0 and 10 g/dL. The diffusion coefficient was also measured with testicular hyaluronidase at three different albumin-concentration differences. The diffusion coefficient increased significantly (P < 0.0001) approximately three-fold from a mean value of 2.2 x 10(-8) +/- 1.2 x 10(-8) (SD) cm2/s at 0-0.5 g/dL delta C to 5.9 x 10(-8) +/- 1.1 x 10(-8) (SD) cm2/s at 10 g/dL delta C. The values are much less than the free diffusion coefficient of albumin (6 x 10(-7) cm2/s). Testicular hyaluronidase added to the albumin solution decreased D by approximately 60%, but did not eliminate the increase in D with delta C. The increase in D with delta C and the reduced D with hyaluronidase were attributed to a reduced albumin-excluded volume caused by an interaction between albumin and hyaluronan. Further studies are required to define this interaction.

Physiological pharmacokinetics of solutes in the isolated perfused rat hindlimb: Characterization of the physiology with changing perfusate flow, protein content, and temperature using statistical moment analysis

Distribution of Evans Blue (EB), sucrose, and water into the isolated perfused rat hindlimb was studied under various conditions using the multiple indicator dilution (MID) technique. Statistical moment analysis of the outflow profiles for the EB, sucrose, and water were used to define the vascular, extravascular, and total water spaces, respectively. The varied perfusion conditions included albumin content (2, 4.7, and 7%), temperature (25, 37, and 42 C), perfusate flow rate (2, 4, 8, and 12 ml/min) and the presence/absence of red blood cells. The range of studies undertaken were chosen to represent the variety of conditions used in the preparation of both isolated animal and human limbs, the latter being particularly important in cytotoxic therapy for recurrent malignant melanoma. The distribution volumes of EB, sucrose, and water were dependent on the flow rate and the albumin content of perfusate. The normalized variances (CV2) of the markers were of the following order: sucrose (2.18) > water (1.58) > EB (0.68), indicating that some disequilibrium occurs during the capillary exchange of water and sucrose. It is suggested that a Krebs-Henseleit buffer containing 2% BSA is a suitable perfusate for most studies of the isolated rat hindlimb perfusion. The effect of albumin concentration manifests itself only at higher flows.

Stereoselective protein binding of ketoprofen: effect of albumin concentration and of the biological system.

Equilibrium dialysis was used to study in vitro the enantioselective binding of R, S, and racemic ketoprofen at physiological pH and temperature in human serum albumin (HSA) (1, 20, and 40 g/liter) and in plasma. The binding of enantiomers in a racemic mixture was studied to see the effect of each isomer on the other's interaction with the protein. The free fractions were determined by high-performance liquid chromatography. The binding of ketoprofen enantiomers to albumin was enantioselective, depending on both drug and protein concentrations. Enantioselectivity was observed in plasma too but was the opposite of that in HSA at 40 g/liter. The percentage of each isomer unbound was higher in the racemic mixture than with the isomer alone. The displacement of probes specific for HSA sites I and II, studied by spectrofluorimetry, suggests that all three preparations of ketoprofen are bound mainly to site I and secondarily to site II.

Binding of pyrimethamine to human plasma proteins and erythrocytes.

A high-performance liquid chromatographic (HPLC) assay was developed for pyrimethamine in plasma, red blood cells (RBCs), and buffer for the purpose of studying its plasma protein binding and RBC partitioning. Pyrimethamine (1000 ng/ml) was 94% bound to plasma proteins on average, depending on the pH of plasma. A comparison of the lower and upper range of plasma concentrations that would be achieved after a malaria prophylaxis dosing regimen (25 mg/week) showed that the fraction unbound was significantly lower at 120 ng/ml than at the upper plasma concentration of 360 ng/ml, 3.5 vs 4.9%, respectively. Nonlinear regression of the effect of albumin concentration (g/L) on plasma binding yielded the equation: fraction unbound = 1/[(0.421 * albumin concentration) + 1] (R2 = 0.99). There was no binding to normal levels of alpha 1-acid glycoprotein (AAG). The mean ratio of the concentration of pyrimethamine in RBCs to that in plasma (RBC:plasma ratio) was 0.42, while the mean RBC:buffer ratio was 5.2. Binding to hemolysate did not account for all of the RBC uptake, suggesting that binding to or partitioning into RBC membranes may be important. Because pyrimethamine binding depends on both albumin concentration and pyrimethamine concentration in the plasma, these studies predict greater free fractions of pyrimethamine associated with the higher doses given for toxoplasmosis (75 mg/day) and with the hypoalbuminemia associated with AIDS and malaria.

Albumin enhances unidirectional fluxes of fatty acid across a lipid-water interface: theory and experiments.

The effect of albumin concentration on the unidirectional fluxes of [3H]oleate across a lipid-water interface was measured by using a new model system consisting of a lipid phase (n-decane) separated from a stirred buffer phase by a planar interface. Albumin (0.15 mM) enhanced the flux of oleate from the lipid phase more than 30-fold. A similar increase in the oleate flux into the lipid was seen when the aqueous oleate and albumin concentrations were increased while keeping the unbound oleate concentration fixed. The ratio of the unidirectional fluxes was constant over the range of albumin concentrations investigated (1-100 microM). Analysis using rigorous rate theory indicated that the permeability of the interfacial surface was flux-limiting at high albumin, whereas diffusion across the unstirred water layer was flux-limiting at low albumin. The observed kinetic patterns are similar to results previously reported in cellular transport systems and attributed to specialized mechanisms for cellular uptake from the albumin-bound pool.

Hepatic uptake of indocyanine green and perfusion rate in rats: effect of age and albumin concentration.

Liver blood flow and hepatic uptake of some indicator substances have been reported to fall with age in both rats and humans. We used an isolated liver system, which was perfused in one pass with hemoglobin free buffer, to investigate the effect of albumin concentration, buffer flow rate, and age upon hepatic clearance of the dye, indocyanine green. We measured the half-life of a bolus of indocyanine green given intravenously to male Sprague-Dawley rats aged 10 and 24 months and then examined its clearance in vitro using their isolated perfused livers. After perfusion, the livers were homogenized and separated into subcellular fractions. The mean liver weight declined significantly (young, 19.7 +/- 2.9 g vs. old, 13.9 +/- 2.6 g; p less than 0.02). In vivo the indocyanine green clearance was reduced in the aged rats (3.2 +/- 1.0 vs. 5.1 +/- 1.7 mL/min; p less than 0.05). In the isolated perfused liver system, extraction ratio showed an inverse curvilinear correlation with albumin concentration and buffer flow rate, but did not differ with age. Hepatic protein content and dye subcellular localization did not differ between the two groups. In conclusion, the fall in indocyanine green clearance in vivo is not paralleled by the ability of the organs to extract the dye in vitro, and likely reflects a decline in hepatic mass and blood flow.

Determination of ionised calcium by ion selective electrode is not independent of albumin concentration

The relationship of ionised calcium measurement to changes in serum total protein and albumin were studied both in vivo and in vitro. During venostasis serum ionised calcium was determined in 10 control subjects using an Orion SS20 analyser. A slight but significant increase in ionised calcium occurred only after prolonged venostasis (15 min), when gross changes in total protein and albumin were seen. The effect of albumin concentration on serum ionised calcium was studied in vitro by the dialysis technique of Payne [6]. The increase in ionised calcium in 40 sera was 0.0198 mmol/l per 10 g albumin change. We conclude that albumin-related variation in serum ionised calcium determination required such gross changes that correction is rarely necessary in clinical practice. When gross albumin alteration occurs, the appropriate correction for the analyser used should be determined and applied.

Effect of albumin concentration on equilibrium radioimmunoassay of serum free thyroxin with labeled thyroxin analog (Amerlex free T4)

Effect of albumin concentration on equilibrium radioimmunoassay of serum free thyroxin with labeled thyroxin analog (Amerlex free T4)

Effect of albumin concentration on the assay of serum free thyroxin by equilibrium radioimmunoassay with labeled thyroxin analog (Amerlex Free T4).

Serum free thyroxin (FT4) in normal nonpregnant and pregnant subjects was measured by radioimmunoassay (RIA) with Amerlex FT4 RIA (Amersham International) and LiquiSol FT4 RIA (Damon Diagnostics) kits. Amerlex FT4 values in serum from pregnant women were lower than those in serum from nonpregnant women, but LiquiSol FT4 values were similar in serum from both groups. Amerlex FT4 values were directly correlated with the concentrations of albumin in serum and inversely correlated with those of thyroxin-binding globulin, but not with prealbumin concentrations. No significant correlations were observed between LiquiSol FT4 values and serum concentrations of thyroxin-binding proteins. Amerlex FT4 values were normal in patients with excess, deficient, or decreased thyroxin-binding globulin. Albumin added to serum samples increased Amerlex FT4 values but not LiquiSol FT4 values. Albumin inhibited the binding of labeled thyroxin analog to the solid-phase thyroxin antibody. These data indicate that the albumin concentration influences FT4 values as measured by an RIA involving a thyroxin analog and that Amerlex FT4 values should be carefully interpreted when the patient has an abnormal concentration of serum albumin.

The effect of albumin concentration and storage time on the adhesion of washed porcine platelets to glass

The effect of storing platelet suspensions at room temperature before assessing platelet adhesiveness to glass was investigated. Changes found in adhesiveness depended on the albumin concentration of the suspension medium. The initial rate of platelet adhesion was inversely related to albumin concentration. Thereafter, during a 4-hr period, platelet adhesion decreased in suspensions with low (0–0.35%) albumin concentrations, whereas at higher concentrations, the adhesion was either not affected (1% albumin) or increased (2% albumin). These observations are explained by the different and opposite effects of albumin which adsorbs to glass more quickly than the platelets and improves the viability of the platelets during storage.

Effect of albumin concentration on function of isolated perfused rat kidney.

ARTICLESEffect of albumin concentration on function of isolated perfused rat kidney Little JR, and JJ Cohen Little JR, and JJ CohenPublished Online:01 Mar 1974https://doi.org/10.1152/ajplegacy.1974.226.3.512MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByOxidation of hyperpolarized [1‐ 13 C]pyruvate in isolated rat kidneys17 November 2022 | NMR in Biomedicine, Vol. 10Isolated rat kidney perfused with dextran and bovine serum albumin: A stable model for investigating renal drug handlingJournal of Pharmacological and Toxicological Methods, Vol. 49, No. 2Downstream effects of splanchnic ischemia-reperfusion injury on renal function and eicosanoid releasePatricia Rothenbach, Richard H. Turnage, Jose Iglesias, Angela Riva, Lori Bartula, and Stuart I. Myers1 August 1997 | Journal of Applied Physiology, Vol. 83, No. 2Role of endothelin in the pathophysiology of renal ischemia-reperfusion in normal rabbitsKidney International, Vol. 50, No. 3Acute mesenteric ischemia/reperfusion down regulates renal PGE2 synthesisProstaglandins, Leukotrienes and Essential Fatty Acids, Vol. 52, No. 1Renal Effects of Multiple Infusion of Pyridoxalated-Hemoglobin-Polyoxyethylene Conjugate (PHP) Solution in Dogs12 November 2008 | Artificial Organs, Vol. 17, No. 3Mild renal ischemia activates primed neutrophils to cause acute renal failureKidney International, Vol. 42, No. 3Role of neutrophil derived oxidants and elastase in lipopolysaccharide-mediated renal injuryKidney International, Vol. 39, No. 4Direct effects of endotoxin on the function of the isolated perfused rat kidneyKidney International, Vol. 37, No. 5A comparison of vasopressin and noradrenaline on oxygen uptake by perfused rat hindlimb, kidney, intestine and mesenteric arcade suggests that it is in part due to contractile work by blood vesselsGeneral Pharmacology: The Vascular System, Vol. 21, No. 5A model of hypoxic renal failureJournal of Surgical Research, Vol. 44, No. 6Oxygen Transport to Renal Tissue: Effect of Oxygen CarriersRenal handling of high-density lipoproteins by isolated perfused kidneysMetabolism, Vol. 33, No. 5Ultrastructure and Intercellular Vacuolization of Isolated Perfused and Control Rat Testes2 January 2013 | Journal of Andrology, Vol. 4, No. 6Rabbit kidney function in vitro: The effect of colloids, energy substrate, a vasodilator, perfusion pressure, and bovine serum albuminCryobiology, Vol. 20, No. 5Hepatic nephropathy, related to haemodynamics10 December 2008 | Liver, Vol. 3, No. 5Renal MetabolismGlomerular filtration in the isolated perfused kidneyPfl�gers Archiv European Journal of Physiology, Vol. 397, No. 1Sodium homeostasis in dogs with chronic renal insufficiencyKidney International, Vol. 21, No. 6RENAL VASODILATOR ACTIVITY OF PROSTAGLANDIN E2 IN THE RAT ANAESTHETIZED WITH PENTOBARBITONE19 July 2012 | British Journal of Pharmacology, Vol. 76, No. 1NUTRITIONAL OEDEMA, ALBUMIN, AND VANADATEThe Lancet, Vol. 317, No. 8221[12] Isolated perfused rat kidneyParacetamol metabolism by the isolated perfused rat kidneyKidney International, Vol. 18, No. 5Fluorescence of pyridine nucleotide and flavoproteins as an indicator of substrate oxidation and oxygen demand of the isolated perfused rat kidneyInternational Journal of Biochemistry, Vol. 12, No. 1-2FLUORESCENCE OF PYRIDINE NUCLEOTIDE AND FLAVOPROTEINS AS AN INDICATOR OF SUBSTRATE OXIDATION AND OXYGEN DEMAND OF THE ISOLATED PERFUSED RAT KIDNEYThe use of urinary N-acetyl-β-glucosaminidase in human renal toxicology I. Partial biochemical characterization and excretion in humans and release from the isolated perfused rat kidneyToxicology and Applied Pharmacology, Vol. 49, No. 2The physiologic determinants of glomerular ultrafiltration30 June 2005Renal Hemodynamic Factors and the Regulation of Sodium ExcretionMethodology for Study of Isolated Perfused Rat Kidney in VitroMechanics of Glomerular UltrafiltrationNew England Journal of Medicine, Vol. 297, No. 3LiteraturRenal blood flow in cirrhosis: relation to systemic and portal haemodynamics and liver function8 July 2009 | Scandinavian Journal of Clinical and Laboratory Investigation, Vol. 37, No. 7The effects of aortic infusion of ethylene oxide on renal function in the ratToxicology and Applied Pharmacology, Vol. 38, No. 2Cellular aspects of renal sodium transport and cell volume regulationKidney International, Vol. 9, No. 2The O2 Supply of the Isolated Cell-Free Perfused Rat KidneyMetabolic Support for Renal Sodium ReabsorptionMedical Clinics of North America, Vol. 59, No. 3The isolated perfused kidney: Possibilities, limitations and resultsKidney International, Vol. 7, No. 1 More from this issue > Volume 226Issue 3March 1974Pages 512-517 Copyright & PermissionsCopyright © 1974 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1974.226.3.512PubMed4817402History Published online 1 March 1974 Published in print 1 March 1974 Metrics

Effect of albumin concentration and ADH on H2O and electrolyte transport in perfused rat kidney.

Effect of albumin concentration and ADH on H2O and electrolyte transport in perfused rat kidney.

Effect of albumin concentration and colloid osmotic pressure on albumin synthesis in the perfused rat liver.

AbstractDich, J., S. E. Hansen and H. I. D. Thieden. Effect of albumin concentration and colloid osmotic pressure on albumin synthesis in the perfused rat liver. Acta physiol. scand. 1973. 89. 352–358.The effect of the albumin concentration and the colloid osmotic pressure on the rate of albumin synthesis was investigated in the perfused rat liver. The albumin concentration and the colloid osmotic pressure were changed independently. With the same concentration of albumin the rate of albumin synthesis decreased 20 to 30 per cent when the colloid osmotic pressure was increased by addition of gammaglobulin. It is concluded that the rate of albumin synthesis may be regulated by the colloid osmotic pressure. The albumin concentration seems to play a role in regulation only through the contribution to the colloid osmotic pressure.

Further studies of binding of bromosulphthalein sodium by human serum albumin: effects of albumin concentration and buffer composition.

1. Binding isotherms of equilibrium solution concentration of bromosulphthalein (BSP) determined on the number of moles of BSP bound per mole of human serum albumin (HSA) in 310 ideal milliosmolar pH 7.4, Krebs-Henseleit and Krebs improved mammalian Ringer number 1 buffers at 37 degrees C were determined using continuous diafiltration. The albumin concentration range was from about 10 to 30 g/litre.2. The results indicate a competition between HSA polymerization and HSA binding BSP, confirming in more physiological conditions, the findings of Crawford, Jones, Thompson & Wells (1972) with pH 7.4 phosphate buffer.3. The results in Krebs-Henseleit buffer were markedly different from those in Krebs mammalian Ringer buffer and it is suggested that the differences in ionic composition influence the HSA conformation and so affect the competition between HSA polymerization and HSA binding BSP.

Effect of albumin concentration on albumin synthesis in the perfused liver.

Effect of albumin concentration on albumin synthesis in the perfused liver.