Dialysate

Distribution by Scientific Domains

Terms modified by Dialysate

  • dialysate concentration
  • dialysate da
  • dialysate level

  • Selected Abstracts


    Increase of matrix metalloproteinase-2 in dialysate of rat sclerosing encapsulating peritonitis model

    NEPHROLOGY, Issue 4 2002
    Ichiro HIRAHARA
    SUMMARY: Sclerosing peritonitis (SP) and sclerosing encapsulating peritonitis (SEP) are serious complications of continuous ambulatory peritoneal dialysis (CAPD). the mortality rate of SP/SEP is extremely high. It is important to clarify the mechanism of progression of SP/SEP, and to prevent this complication. We prepared an animal model of SEP by intraperitoneal administration of chlorhexidine gluconate (CHX) using male Sprague-Dawley rats. Dialysate drained from these animals was analysed by gelatin zymography. In this animal model of SEP, fibrous peritoneal thickening accompanied by cellular infiltration and peritoneal adhesion, were observed. Four of six rats presented with a so-called abdominal cocoon. an increase of peritoneal absorption of glucose was also confirmed. Zymographic analysis revealed that the matrix metalloproteinase-2 (MMP-2) level was high in the dialysate from the animal model, although MMP-9 was hardly detected. From these results, the MMP-2 level in drained dialysate was considered to increase in SP/SEP. Matrix metalloproteinase-2 might be associated with the progression of SP/SEP. [source]


    Oxytocin injected into the ventral tegmental area induces penile erection and increases extracellular dopamine in the nucleus accumbens and paraventricular nucleus of the hypothalamus of male rats

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007
    Maria Rosaria Melis
    Abstract The neuropeptide oxytocin (20,100 ng), induces penile erection when injected unilaterally into the caudal but not rostral mesencephalic ventral tegmental area (VTA) of male Sprague,Dawley rats. Such pro-erectile effect started 30 min after treatment and was abolished by the prior injection of d(CH2)5Tyr(Me)2 -Orn8 -vasotocin (1 µg), an oxytocin receptor antagonist injected into the same caudal ventral tegmental area or of haloperidol (1 µg), a dopamine receptor antagonist, injected either into the nucleus accumbens shell (NAs) or into the paraventricular nucleus of the hypothalamus (PVN) ipsilateral to the injected ventral tegmental area. Penile erection was seen 15 min after the occurrence of, or concomitantly to, an increase in extracellular dopamine and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the dialysate obtained from the nucleus accumbens or the paraventricular nucleus, which was also abolished by d(CH2)5Tyr(Me)2 -Orn8 -vasotocin (1 µg), injected into the ventral tegmental area before oxytocin. In the caudal ventral tegmental area oxytocin-containing axons/fibres (originating from the paraventricular nucleus) appeared to closely contact cell bodies of mesolimbic dopaminergic neurons retrogradely labelled with Fluorogold injected into the nucleus accumbens shell, suggesting that oxytocin effects are mediated by the activation of mesolimbic dopaminergic neurons, followed in turn by that of incerto-hypothalamic dopaminergic neurons impinging on oxytocinergic neurons mediating penile erection. As the stimulation of paraventricular dopamine receptors not only induces penile erection, but also increases mesolimbic dopamine neurotransmission by activating oxytocinergic neurons, these results provide further support for the existence of a neural circuit in which dopamine and oxytocin influence both the consummatory and motivational/rewarding aspects of sexual behaviour. [source]


    Extracellular excitatory amino acids increase in the paraventricular nucleus of male rats during sexual activity: main role of N -methyl- d -aspartic acid receptors in erectile function

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2004
    Maria Rosaria Melis
    Abstract The concentrations of glutamic and aspartic acids were measured in the dialysate obtained with vertical microdialysis probes implanted into the paraventricular nucleus of the hypothalamus of sexually potent male rats during sexual activity. Animals showed noncontact erections when put in the presence of, and copulated with, a receptive (ovarietomized oestrogen- and progesterone-primed) female rat. The concentrations of glutamic and aspartic acids in the paraventricular dialysate increased by 37 and 80%, respectively, above baseline values during exposure to the receptive female rat and by 55 and 127%, respectively, during copulation. No changes in the concentrations of glutamic and aspartic acids were detected in the paraventricular dialysate when sexually potent male rats were exposed to nonreceptive (ovariectomized not oestrogen- and progesterone-primed) female rats or when impotent male rats were used. The injection into the paraventricular nucleus of the excitatory amino acid receptor antagonist dizocilpine (5 µg), a noncompetitive N -methyl- d -aspartic acid receptor antagonist, reduced noncontact erections and significantly impaired copulatory activity. The ,-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist 6-cyano-7-nitro-quinoxaline-2,3-dione (5 µg) was also able to impair copulatory activity, but to a much lower extent than dizocilpine. In contrast, (±)-2-amino-4-phosphono-butanoic acid, a metabotropic receptor antagonist (5 µg), was found to be ineffective. These results confirm the involvement of the paraventricular nucleus in the control of erectile function and copulatory behaviour and show that excitatory amino acid concentration increases in the paraventricular nucleus when penile erection occurs in physiological contexts. [source]


    Extra-cellular dopamine increases in the paraventricular nucleus of male rats during sexual activity

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2003
    Maria Rosaria Melis
    Abstract Dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations were measured in the dialysate obtained with vertical microdialysis probes implanted into the paraventricular nucleus of the hypothalamus of sexually potent male rats. Animals showed noncontact erections when put in the presence of, and copulated with a receptive (ovarietomized oestrogen and progesterone primed) female rat. Dopamine and DOPAC concentrations in the paraventricular dialysate increased 140% and 19%, respectively, above baseline values during exposure to the receptive female and 280% and 31%, respectively, during copulation. No changes in dopamine and DOPAC concentrations were detected in the paraventricular dialysate when sexually potent male rats were exposed to nonreceptive (ovariectomized not oestrogen plus progesterone primed) female rats. These results confirm the involvement of the paraventricular nucleus in control of erectile function and copulatory behaviour and show for the first time that dopamine neurotransmission is increased in this hypothalamic nucleus when erection occurs in physiological contexts. [source]


    The Neurogenic Vasodilator Response to Endothelin-1: A Study in Human Skin In Vivo

    EXPERIMENTAL PHYSIOLOGY, Issue 6 2000
    Ruwani Katugampola
    We have investigated the mediators and mechanisms underlying the vasodilator effects of the potent vasoactive peptide, endothelin-1 (ET-1) and its isomers ET-2 and ET-3 in human skin, in vivo, using cutaneous microdialysis to quantify the release of mediators within the dermal response and scanning laser Doppler imaging to measure changes in blood flux. The effects of local anaesthesia, inhibition of nitric oxide synthase (NOS) by L-NAME and ET receptor blockade on the ET-induced vascular response were also investigated. ET-1, -2 and -3 all caused a dose-dependent area of pallor surrounded by a long-lasting flare which was accompanied by a short-lived burning pruritus. The concentration of nitric oxide (NO) in dialysate collected within the pallor response to 5 ,M ET-1 (1.43 ± 0.64 ,M, n = 5) was not significantly different from baseline levels collected prior to injection (0.86 ± 0.38 ,M) whilst that in the flare increased to reach a peak value of 2.28 ± 0.61 ,M at between 4 and 10 min after intradermal injection (P < 0.004). Pretreatment with local anaesthetic slowed the development of the flare and significantly reduced its size by up to 52% at 20 min after injection (P < 0.05) but had no significant effect on the central pallor. L-NAME, delivered by dialysis also caused a significant reduction in the ET-1-induced flare (P < 0.005). Bosentan, the non-selective ETA/ETB antagonist, when given by dialysis at the site of injection, reduced the area of both the ET-1-induced pallor and surrounding flare by 41 and 26%, respectively. No significant increase in tissue histamine was measured within either the pallor or flare response to ET-1, -2 or -3. Together these data confirm that the vasodilator response to endothelin-1 in human skin is neurogenic in origin and that it is in part mediated by the local release of nitric oxide. There appears to be little evidence for the involvement of mast cell-derived histamine in the initiation or modulation of ET-induced vasodilatation, in vivo. [source]


    Utility of citrate dialysate in management of acute kidney injury in children

    HEMODIALYSIS INTERNATIONAL, Issue 2010
    Coral HANEVOLD
    Abstract Dialysis concentrate acidified with citrate as opposed to acetate has been reported to prevent clotting in hemodialysis circuits, and improve dialysis efficiency in adults. There is no information on its use in children. The purpose of the study was to evaluate the utility of citrate dialysate for renal replacement therapy in a pediatric population with acute kidney injury. We performed a retrospective review of our experience using Citrasate® concentrate from December 2007 to August 2009. All treatments were provided using the Fresenius 2008 dialysis machine. Citrasate® was utilized in 7 children aged 60.3±51.0 months (mean±SD), range 13 months to 12 years. The number of treatments varied from 4 to 31 (mean 12±8 treatments) for a total of 89 treatments. Rare sporadic mild hypocalcemia was noted but could not be definitively linked with the use of Citrasate®. Four children also required low-dose heparin (3.6,15 U/kg/h) due to clotting. Activated clotting times (when checked) were not affected by this low-dose heparin therapy. Some degree of clotting occurred in 21 of 89 (23.5%) treatments. Early termination of treatment due to thrombosis was required in 7 of 89 (7.8%) treatments. In summary, use of Citrasate® dialysis concentrate was well tolerated in critically ill children with acute kidney injury. Citrasate® reduced but did not completely eliminate the need for heparin in our population. Further study in a more diverse population would be helpful. [source]


    Cool dialysate reduces asymptomatic intradialytic hypotension and increases baroreflex variability

    HEMODIALYSIS INTERNATIONAL, Issue 2 2009
    Lindsay J. CHESTERTON
    Abstract Intradialytic hypotension (IDH) remains an important cause of morbidity and mortality in chronic hemodialysis (HD) patients and can be ameliorated by cool temperature HD. The baroreflex arc is under autonomic control and is essential in the short-term regulation of blood pressure (BP). This study aimed to investigate if the baroreflex sensitivity (BRS) response to HD differed between standard and cool-temperature dialysate. Ten patients (mean age 67±2 years) prone to IDH were recruited into a randomized, crossover study to compare BRS variation at dialysate temperatures of 37 °C (HD37) and 35 °C (HD35). Each patient underwent continuous beat-to-beat BP monitoring during a dialysis session of HD37 and HD35. During HD37 2 patients developed symptomatic IDH, as opposed to 1 with HD35. However, asymptomatic IDH occurred with a frequency of 0.4 episodes per session with HD35 and 6.2 episodes per session during HD37 (odds ratio15.5; 95%CI 5.6,14.2). Although absolute BRS measurements did not differ between the 2 modalities, BRS variability increased during HD35. Our study has demonstrated that in IDH-prone patients, cool HD resulted in a reduction in heart rate and a greater reduction in cardiac output and stroke volume. Mean arterial pressure was maintained through a significantly greater increase in total peripheral resistance. Furthermore, although absolute BRS values during HD were not significantly altered by a reduction in dialysate temperature, there was a greater percentage increase in BRS values during cool HD. Understanding the varied causes of, and categorizing impaired hemodynamic responses to HD will enable further individualization of HD prescriptions according to patient need. [source]


    Prediction of hemodialysis sorbent cartridge urea nitrogen capacity and sodium release from in vitro tests

    HEMODIALYSIS INTERNATIONAL, Issue 2 2008
    Benjamin P. ROSENBAUM
    Abstract In sorbent-based hemodialysis, factors limiting a treatment session are urea conversion capacity and sodium release from the cartridge. In vitro experiments were performed to model typical treatment scenarios using various dialyzers and 4 types of SORBÔ sorbent cartridges. The experiments were continued to the point of column saturation with ammonium. The urea nitrogen removed and amount of sodium released in each trial were analyzed in a multi-variable regression against several variables: amount of zirconium phosphate (ZrP), dialysate flow rate (DFR), simulated blood flow rate (BFR), simulated patient whole-body fluid volume (V), initial simulated patient urea concentration (BUNi), dialyzer area permeability (KoA) product, initial dialysate sodium and bicarbonate (HCO3i) concentrations, initial simulated patient sodium (Nai), pH of ZrP, creatinine, breakthrough time, and average urea nitrogen concentration in dialysate. The urea nitrogen capacity (UNC) of various new SORBÔ columns is positively related to ZrP, BFR, V, BUNi, and ZrP pH and negatively to DFR with an R2adjusted=0.990. Two models are described for sodium release. The first model is related positively to DFR and V and negatively to ZrP, KoA product, and dialysate HCO3i with an R2adjusted=0.584. The second model incorporates knowledge of initial simulated patient sodium (negative relationship) and urea levels (negative relationship) in addition to the parameters in the first model with an R2adjusted=0.786. These mathematical models should allow for prediction of patient sodium profiles and the time of column urea saturation based on simple inputs relating to patient chemistries and the dialysis treatment. [source]


    Effect of acetate-free biofiltration with a potassium-profiled dialysate on the control of cardiac arrhythmias in patients at risk: A pilot study

    HEMODIALYSIS INTERNATIONAL, Issue 1 2008
    Rosa I. MUÑOZ
    Abstract Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia. [source]


    Comparison between different dialysate calcium concentrations in nocturnal hemodialysis

    HEMODIALYSIS INTERNATIONAL, Issue 2 2007
    Nigel D. TOUSSAINT
    Abstract Benefits of dialysate with greater calcium (Ca) concentration are reported in nocturnal hemodialysis (NHD) to prevent Ca depletion and subsequent hyperparathyroidism. Studies with patients dialyzing against 1.25 mmol/L Ca baths demonstrate increases in alkaline phosphatase (ALP) and parathyroid hormone (PTH) and increasing dialysate Ca subsequently corrects this problem. However, whether 1.5 or 1.75 mmol/L dialysate Ca is most appropriate for NHD is yet to be determined, and differences in the effect on mineral metabolism of daily vs. alternate daily NHD have also not been well defined. We retrospectively analyzed mineral metabolism in 48 patients, from 2 institutions (30 at Monash and 18 at Geelong), undergoing home NHD (8 hr/night, 3.5,6 nights/week) for a minimum of 6 months. Thirty-seven patients were dialyzed against 1.5 mmol/L Ca bath and 11 patients against 1.75 mmol/L. We divided patients into 4 groups, based on dialysate Ca and also on the hours per week of dialysis, <40 (1.5 mmol/L, n=29 and 1.75 mmol/L, n=8) or ,40 (n=4 and 7). We compared predialysis and postdialysis serum markers, time-averaged over a 6-month period, and the administration of calcitriol and Ca-based phosphate binders between 1.5 and 1.75 mmol/L Ca dialysate groups. Baseline characteristics between all groups were similar, with a slightly longer, but nonsignificant, duration of NHD in both 1.75 mmol/L dialysate groups compared with 1.5 mmol/L. The mean predialysis Ca, phosphate, and Ca × P were similar between the 1.5 and 1.75 mmol/L groups, regardless of NHD hr/week. Postdialysis Ca was significantly greater, with 1.75 vs. 1.5 mmol/L in those dialyzing <40 hr/week (2.64±0.19 vs. 2.50±0.12 mmol/L, p=0.046), but postdialysis Ca × P were similar (2.25±0.44 vs. 2.16±0.29 mmol2/L2, p=0.60). Parathyroid hormone was also lower with 1.75 vs. 1.5 mmol/L baths in the <40 hr/week groups (31.99±26.99 vs. 14.47±16.36 pmol/L, p=0.03), although this difference was not seen in those undertaking NHD ,40 hr/week. Hemoglobin, ALP, and albumin were all similar between groups. There was also no difference in vitamin D requirement when using 1.75 mmol/L compared with the 1.5 mmol/L dialysate. Multivariate analysis to determine independent predictors of postdialysis serum Ca showed a statistically significant positive association with predialysis Ca, dialysate Ca, and total NHD hr/week. An elevated dialysate Ca concentration is required in NHD to prevent osteopenia but differences in serum markers of mineral metabolism between 1.5 and 1.75 mmol/L Ca dialysate in NHD in our study were few. This was similar for patients undertaking NHD <40 or ,40hr/week, although differences in the frequency of NHD may also be as important as dialysate Ca with regard to serum Ca levels. With concerns that prolonged higher Ca levels contribute to increased cardiovascular mortality, the optimal Ca dialysate bath is still unknown and further studies addressing bone metabolism with larger NHD numbers are required. [source]


    Ionic dialysance: Principle and review of its clinical relevance for quantification of hemodialysis efficiency

    HEMODIALYSIS INTERNATIONAL, Issue 2 2005
    Lucile Mercadal
    Ionic dialysance (D) is an online measured variable now available on several dialysis monitors to evaluate small-solute clearance. Based on conductivity measurements in the inlet and outlet dialysate, the principle of the measurement and the different measurement methods are described. Studies that have evaluated the reliability of ionic dialysance to assess dialysis efficiency are discussed. These studies are divided into two groups: the first comparing ionic dialysance to urea clearance and the second comparing Dt/V to Kt/Vurea, in which the uncertainties of the measurement of Vurea could have misrepresented the relationship between Dt/V and Kt/Vurea. When Kt/Vurea via the Daugirdas second-generation equation taking the rebound into account is considered, slight,even nonsignificant,differences are evidenced between Kt/Vurea and Dt/V. Therefore, ionic dialysance should be considered as a valid measure in future guidelines for dialysis efficiency. [source]


    Overproduction of reactive oxygen species in end-stage renal disease patients: A potential component of hemodialysis-associated inflammation

    HEMODIALYSIS INTERNATIONAL, Issue 1 2005
    Marion Morena
    Abstract During the past decade, hemodialysis (HD)-induced inflammation has been linked to the development of long-term morbidity in end-stage renal disease (ESRD) patients on regular renal replacement therapy. Because interleukins and anaphylatoxins produced during HD sessions are potent activators for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, an example of an enzyme that is responsible for overproduction of reactive oxygen species (ROS), this may constitute a link between leukocyte activation and cell or organ toxicity. Oxidative stress, which results from an imbalance between oxidant production and antioxidant defense mechanisms, has been documented in ESRD patients using lipid and/or protein oxidative markers. Characterization of HD-induced oxidative stress has included identification of potential activators for NADPH oxidase. Uremia per se could prime phagocyte oxidative burst. HD, far from improving the oxidative status, results in an enhancement of ROS owing to hemoincompatibility of the dialysis system, hemoreactivity of the membrane, and trace amounts of endotoxins in the dialysate. In addition, the HD process is associated with an impairment in antioxidant mechanisms. The resulting oxidative stress has been implicated in long-term complications including anemia, amyloidosis, accelerated atherosclerosis, and malnutrition. Prevention of oxidative stress in HD might focus on improving the hemocompatibility of the dialysis system, supplementation of deficient patients with antioxidants, and modulation of NADPH oxidase by pharmacologic approaches. [source]


    Experimental study on a new type citrate anticoagulant hemodialysate in dogs

    HEMODIALYSIS INTERNATIONAL, Issue 1 2005
    G. Baosong
    Objective:,In this study, we initiated a new hemodialysate with citrate buffer, observed the factors that influence the citrate concentration of solution in hollow fibers when using citrate hemodialysate, and observed the anticoagulant effect and safety of the citrate hemodialysate in the experiment in dogs. Methods:,Ten dogs were given intermittent hemodialysis and were divided into 3 groups according to hemodialysis procedures. Group 1 was saline-flush hemodialysed with bicarbonate hemodialysate; Group 2 was hemodialysed with citrate hemodialysis without any anticoagulant; Group 3 was hemodialysed with bicarbonate hemodialysate and heparin. ACT, Ca++, BUN, Cr, ALT, AST, TBIL, DBIL, Na+, Cl,, , and venous pressure were monitored in the animals of each group during hemodialysis. Results:,During the hemodialysis in Group 1, venous pressure increased lastingly, resulting in the failure of hemodialysis for 2 hours. Hemodialysis for 2 hours in Group 2 were all finished successfully. ACT was extended and Ca++ decreased obviously in the venous end during hemodialysis. And ALT, AST, Ca++, K+, Na+, Cl,, after the hemodialysis in Group 2 were not changed (P > 0.05). Moreover, the clearance rate of the dialyzers with citrate dialysate increased significantly compared with those of saline-flush and heparin anticoagulation. Conclusions:,The anticoagulant and dialytic effects of the new type citrate hemodialysis are satisfactory and better than that of saline-flush. [source]


    An Incenter Nocturnal Hemodialysis Program,Three Years Experience

    HEMODIALYSIS INTERNATIONAL, Issue 1 2003
    M. Gene Radford
    We report our experience with a program of long, slow, overnight hemodialysis (HD) performed 3 times a week in an existing dialysis facility. Beginning in April 1999, 14 chairs in one bay of our facility were replaced with beds, subdued lighting was installed, and machine alarms were decreased to minimum volume. Fresenius F60 dialyzers were selected with a QB of 220,300 ml/min and a QD of 400,500 ml/min. Patients dialyze for 7,8 hrs overnight. Staffing is with 1 nurse and 1 PCT for 10 patients. Standard dialysate is used, and heparin is dosed 100 U/kg at treatment initiation and again at mid-treatment. All access types are utilized. The program is open to all patients in our area. A total of 65 patients have participated, with a current census of 20 patients. Participants have tried nocturnal dialysis for a variety of reasons including work/school schedules, excessive interdialytic weight gains, inadequate dialysis (due to poor access function or large body mass), and hemodynamic instability with standard daytime HD. Blood pressure control has improved among the participants in the program, perhaps due to more gentle ultrafiltration and improvement in maintenance of dry weight. Among 31 patients who remained on nocturnal dialysis for over 6 months, 21 started the program on an average of 2.5 antihypertensive agents (AHA). After 6 months, 9 patients no longer needed AHA while 12 patients remain on an average of 1.3 AHA. URR also improved by an average of 4.35 among 13 patients who transferred from standard incenter HD to the nocturnal program. In all, 45 patients have left the program, for reasons which include insomnia/social (15), death (9), transfer to home HD (8), renal transplantation (6), noncompliance (3), moved away (2), and other (2). In conclusion, long overnight HD can be performed in an existing dialysis facility, providing patients with another HD option. Patients who may benefit from this modality include those with daytime jobs, patients with inadequate clearance on standard HD, patients with excessive interdialytic weight gains, and those who poorly tolerate standard HD. [source]


    Nocturnal Haemodialysis , A Preliminary Cost Comparison with Conventional Haemodialysis in Australia

    HEMODIALYSIS INTERNATIONAL, Issue 1 2003
    JWM Agar
    A 6 night/wk, home-based, government funded nocturnal haemodialysis (NHDx) program, believed to be the first outside North America, commenced in July 2001. Previously published Canadian and US costs suggest NHDx to be more cost-efficient than conventional haemodialysis (CHDx) as, although consumable-expensive, NHDx is home-based and is thus highly infrastructure, wage and hospital inpatient bed-day efficient. Comparable Australian cost evaluation is essential, however, before NHDx is widely encouraged as a new modality here. Cost comparisons for 3 × wk CHDx vs preliminary costs for 9/12 pts on 6 × wk NHDx (3 excluded for inadequate program time) include: consumables/fluids CHDx @$A8781/pt/yr vs NHDx @$A17562/pt/yr; estimated nursing costs CHDx (62.25 nurse hrs/wk with a nurse/pt ratio of 3:9)@$A12666/pt/yr vs NHDx (40 nurse hrs/wk with a nurse/pt ratio of 1:9)@$A8111/pt/yr with projected reduction to A$4866 for nurse/pt ratio of 1:15; pharmaceutical costs (includes all medication & Fleet® for dialysate but excludes EPO/iron polymaltose) CHDx one month prior to NHDx @$A1412/pt/yr vs NHDx costs after one month starting home-based treatment @$A1273/pt/yr. Though the NHDx pts have been carefully selected, only 3 hospitalizations for a total of 4 bed-days have been necessary in 348.5 pt wks of experience to September 2002. Our preliminary cost analyses confirm prior North American data. Cumulative financial modeling shows NHDx is more costly than CHDx at low pt numbers, reaching approximate equivalence @ 12 pts and progressively dropping below CHDx costs thereafter. NHDx appears cost-competitive with CHDx whilst yielding superior biochemical, life-style and rehabilitation results (see accompanying clinical data abstract). [source]


    Acute Postdialysis Changes in Plasma ICAM-1 and IL-1 Levels in Hemodialysis Patients

    HEMODIALYSIS INTERNATIONAL, Issue 1 2003
    S EL-Hefeni
    Fifty subjects: 20 controls and 30 hemodialysis patients were included in the study. The acute changes in plasma ICAM-1 and IL-1, levels immediately after dialysis were evaluated using two types of membranes and two types of dialysate. The predialysis ICAM-1 level in the whole patients was significantly higher than controls, while that of IL-1, was significantly lower. The postdialysis ICAM-1 showed insignificant higher level than the predialysis one, while that of IL-1, showed significant higher level than both the predialysis and control levels. Both postdialysis ICAM-1 and IL-1, levels in patients using cuprophane membrane (bioincompatible) showed insignificant higher levels than in those using polysulfone one (biocompatible). The percent increase in ICAM-1 level did not significantly differ in these two subgroups, while the percent increase in IL-1, level showed significantly higher value in those using bioincompatible membrane (108%) than that in those using biocompatible membrane (44%). No significant difference in the levels of either ICAM-1 or IL-1, were found between patients using acetate and bicarbonate dialysate. Conclusion: the bioincompatibility of the membrane is the important factor in the occurrence of the acute reaction during hemodialysis. [source]


    The penetration enhancement and the lipolytic effects of TAT,GKH, both in in vitro, ex vivo, and in vivo

    INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2004
    J. Lim
    It was demonstrated that the trans-activating transcriptional activator (TAT) protein from HIV-1 could enter cells when added to the surrounding media. TAT peptide chemically attached to various proteins was able to deliver these proteins to various cells and even at high levels in heart and spleen tissues in mice. In this study, the tri-peptide GKH (glycine,lysine,histidine) derived from the parathyroid hormone, which is known as a lipolytic peptide, was attached to 9-poly lysine (TAT) to be used as a cosmetic ingredient for eye-bag care product. When glycerol is released, expressed as the extracellular glycerol concentration (the so-called lipolysis index), TAT,GKH at 10,5m induces a maximal lipolytic effect of approximately 41.5% in epididymal adipocytes isolated from rats, compared with basal lipolysis. In a microdialysis study, TAT,GKH was perfused into epididymal adipose tissues of anaesthetized rats in increasing concentrations in a Ringer solution. The glycerol concentration in each dialysate was measured using an ultra-sensitive radiometric method. The perfusion of TAT,GKH induced a lipolytic effect. A penetration study showed that TAT,GKH resulted in a sevenfold higher penetration into excised hairless mice skin than GKH. An in vivo study showed that a TAT,GKH containing emulsion had a better effect upon the relative volume reduction of eye bag after 28 days of application on 22 healthy female volunteers than the placebo. It was therefore concluded that TAT,GKH increased skin penetration, which resulted in enhanced lipolytic effects in in vitro, ex vivo and in volume reduction of eye-bags in in vivo studies. [source]


    Microdialysis measures of functional increases in ACh release in the hippocampus with and without inclusion of acetylcholinesterase inhibitors in the perfusate

    JOURNAL OF NEUROCHEMISTRY, Issue 3 2006
    Qing Chang
    Abstract Because brain extracellular acetylcholine (ACh) levels are near detection limits in microdialysis samples, an acetylcholinesterase (AChE) inhibitor such as neostigmine is often added to microdialysis perfusates to increase ACh levels in the dialysate, a practice that raises concerns that the inhibitor might alter the results. Two experiments compared functional differences in ACh release with and without neostigmine. In the first experiment, 30,60% increases in extracellular ACh concentrations in the hippocampus were evident during food-rewarded T-maze training with 20,500 nm neostigmine in the perfusate but no increases were seen without neostigmine. In the second experiment, 78% increases in ACh release in the hippocampus were seen after injections of the GABAA receptor antagonist, bicuculline, into medial septum only if neostigmine (50 nm) was included in the perfusate. These findings suggest that, in the hippocampus, endogenous brain AChEs are very efficient at removing extracellular ACh, obscuring differences in ACh release in these experiments. Therefore, inclusion of AChE inhibitors in the microdialysis perfusate may be necessary under some conditions for observations of functional changes in release of ACh in the hippocampus. [source]


    Effect of Acute Ethanol Administration on the Release of Opioid Peptides From the Midbrain Including the Ventral Tegmental Area

    ALCOHOLISM, Issue 6 2009
    Samuel Jarjour
    Background:, Experimental evidence suggests that ethanol alters the activity of the endogenous opioid peptide systems in a dose and brain-region dependent manner. These alterations may influence the processes of ethanol reward and reinforcement. Thus, it was the objective of this study to investigate the response of the 3 major opioid peptide systems (endorphins, enkephalins, and dynorphins) to acute ethanol administration, at the level of the midbrain including the ventral tegmental area (midbrain/VTA), a region important for drug, including ethanol reinforcement. Methods:, Using the in vivo microdialysis technique coupled with specific solid-phase radioimmunoassay for ,-endorphin, met-enkephalin, and dynorphin A1,8, changes in the extracellular concentration of theses peptides at the level of midbrain/VTA were determined at distinct time points following the administration of 0.0 (saline), 0.8, 1.2, 1.6, 2.0, and 2.4 g ethanol/kg B.Wt. Results:, A biphasic effect of ethanol on ,-endorphin release was found, with low to medium (1.2, 1.6, and 2.0 g) but not high (2.4 g) doses of ethanol, inducing a significant increase in the dialysate content of ,-endorphin. A late increase in the dialysate content of dynorphin A1,8 was observed in response to the 1.2 g ethanol dose. However, none of the ethanol doses tested significantly altered the content of met-enkephalin in the dialysate. Conclusions:, The present findings suggest that the ethanol-induced increase of ,-endorphin release at the level of midbrain/VTA may influence alcohol reinforcement. [source]


    TOWARD GREENER DIALYSIS: A CASE STUDY TO ILLUSTRATE AND ENCOURAGE THE SALVAGE OF REJECT WATER

    JOURNAL OF RENAL CARE, Issue 2 2010
    Andrew Connor MRCP
    SUMMARY Climate change is now considered to be a major global public health concern. However, the very provision of health care itself has a significant impact upon the environment. Action must be taken to reduce this impact. Water is a precious and finite natural resource. Vast quantities of high-grade water are required to provide haemodialysis. The reverse osmosis systems used in the purification process reject approximately two-thirds of the water presented to them. Therefore, around 250 litres of ,reject water' result from the production of the dialysate required for one treatment. This good quality reject water is lost-to-drain in the vast majority of centres worldwide. Simple methodologies exist to recycle this water for alternative purposes. We describe here a case study of the only UK renal service we know to have implemented such water-saving methodologies. We outline the benefits in terms of financial and environmental savings. [source]


    A Microdialysis Profile of Dynorphin A1,8 Release in the Rat Nucleus Accumbens Following Alcohol Administration

    ALCOHOLISM, Issue 6 2006
    Peter W. Marinelli
    Background: Pharmacological studies have implicated the endogenous opioid system in mediating alcohol intake. Other evidence has shown that alcohol administration can influence endorphinergic and enkephalinergic activity, while very few studies have examined its effect on dynorphinergic systems. The aim of the present study was to investigate the effect of alcohol administration or a mechanical stressor on extracellular levels of dynorphin A1,8 in the rat nucleus accumbens,a brain region that plays a significant role in the processes underlying reinforcement and stress. Methods: Male Sprague,Dawley rats were implanted with a microdialysis probe aimed at the shell region of the nucleus accumbens. Artificial cerebrospinal fluid was pumped at a rate of 1.5 ,L/min in awake and freely moving animals and the dialysate was collected at 30-minute intervals. In one experiment, following a baseline period, rats were injected intraperitoneally with either physiological saline or 1 of 3 doses of alcohol, 0.8, 1.6, or 3.2 g ethanol/kg body weight. In a second experiment, following a baseline period, rats were applied a clothespin to the base of their tail for 20 minutes. The levels of dynorphin A1,8 in the dialysate were analyzed with solid-phase radioimmunoassay. Results: Relative to saline-treated controls, an alcohol dose of 1.6 and 3.2 g/kg caused a transient increase in the extracellular levels of dynorphin A1,8 in the first 30 minutes of alcohol administration. However, the effect resulting from the high 3.2 g/kg dose was far more pronounced and more significant than with the moderate dose. There was no effect of tail pinch on dynorphin A1,8 levels in the nucleus accumbens. Conclusions: In this experiment, a very high dose of alcohol was especially capable of stimulating dynorphin A1,8 release in the nucleus accumbens. Dynorphin release in the accumbens has been previously associated with aversive stimuli and may thus reflect a system underlying the aversive properties of high-dose alcohol administration. However, the lack of effect of tail-pinch stress in the present study suggests that dynorphin A1,8 is not released in response to all forms of stressful/aversive stimuli. [source]


    Differential Increase in Taurine Levels by Low-Dose Ethanol in the Dorsal and Ventral Striatum Revealed by Microdialysis With On-Line Capillary Electrophoresis

    ALCOHOLISM, Issue 7 2004
    A Smith
    Ethanol increases taurine efflux in the nucleus accumbens or ventral striatum (VS), a dopaminergic terminal region involved in positive reinforcement. However, this has been found only at ethanol doses above 1 g/kg intraperitoneally, which is higher than what most rats will self-administer. We used a sensitive on-line assay of microdialysate content to test whether lower doses of ethanol selectively increase taurine efflux in VS as opposed to other dopaminergic regions not involved in reinforcement (e.g., dorsal striatum; DS). Adult male rats with microdialysis probes in VS or DS were injected with ethanol (0, 0.5, 1, and 2 g/kg intraperitoneally), and the amino acid content of the dialysate was measured every 11 sec using capillary electrophoresis and laser-induced fluorescence detection. In VS, 0.5 g/kg ethanol significantly increased taurine levels by 20% for 10 min. A similar increase was seen after 1 g/kg ethanol, which lasted for about 20 min after injection. A two-phased taurine efflux was observed with the 2.0 g/kg dose, where taurine was increased by 2-fold after 5 min but it remained elevated by 30% for at least 60 min. In contrast, DS exhibited much smaller dose-related increases in taurine. Glycine, glutamate, serine, and ,-aminobutyric acid were not systematically affected by lower doses of ethanol; however, 2 g/kg slowly decreased these amino acids in both brain regions during the hour after injection. These data implicate a possible role of taurine in the mechanism of action of ethanol in the VS. The high sensitivity and time resolution afforded by capillary electrophoresis and laser-induced fluorescence detection will be useful for detecting subtle changes of neuronally active amino acids levels due to low doses of ethanol. [source]


    Use of the molecular adsorbents recirculating system as a treatment for acute decompensated wilson disease

    LIVER TRANSPLANTATION, Issue 10 2008
    Alexander Chiu
    Acute decompensated Wilson disease presenting as fulminant liver failure is a life-threatening condition for which liver transplantation is the ultimate treatment. It is listed as a status 1 indication according to the United Network for Organ Sharing classification. A massive amount of copper released during the attack induces hemolytic anemia and acute renal failure. Conventional chelating therapy attempting to remove copper from the patient is not satisfactory because there is inadequate time for these drugs to take action and patients are usually oliguric. The Molecular Adsorbents Recirculating System (MARS) is a form of modified dialysis that removes putative albumin-bound toxins associated with liver failure. It is believed that extracorporeal albumin dialysate absorbs the circulating copper molecules that are trapped in the patient's circulation. We report 2 patients with acute decompensated Wilson disease treated with MARS. In the first case, the patient was started on MARS once conventional treatment failed. A significant amount of copper was removed from her circulatory system, and her condition stabilized afterwards. The treatment gained her extra time, and she was eventually bridged to liver transplantation. In the second case, the patient was started on MARS treatment early in the course of his illness, and his condition soon stabilized after the treatment. He was able to return to his home country for liver transplantation. In both cases, MARS was used as a means of preventing deterioration rather than salvaging devastation. In conclusion, MARS may confer benefits to patients with acute decompensated Wilson disease if it is started early in the course of illness. Liver Transpl 14:1512,1516, 2008. © 2008 AASLD. [source]


    Higher rate and earlier peritonitis in Aboriginal patients compared to non-Aboriginal patients with end-stage renal failure maintained on peritoneal dialysis in Australia: Analysis of ANZDATA

    NEPHROLOGY, Issue 2 2005
    WAI H LIM
    SUMMARY Background: Aboriginal patients maintained on peritoneal dialysis (PD) have a higher rate of technique failure than any other racial group in Australia. Peritonitis accounts for the bulk of these technique, failures,, but, it, is, uncertain, whether, the, increased, risk, of, peritonitis, in, Aboriginal, patients was independent of associated comorbid conditions, such as diabetes mellitus. Methods: Using data collected by the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA), peritonitis rates and time to first peritonitis were compared between Aboriginal (n = 238) and non-Aboriginal patients (n = 2924) commencing PD in Australia between 1 April 1999 and 31 March 2003. Results: Aboriginal PD patients were younger, and had a higher incidence of diabetes than their non-Aboriginal counterparts. Mean peritonitis rates were significantly higher among Aboriginal (1.15 episodes/year; 95% confidence interval (CI): 1.03,1.28) than non-Aboriginal patients (0.60 episodes/year; 95% CI: 0.57,0.62, P < 0.05). Using multivariate negative binomial regression, independent predictors of higher peritonitis rates include Aboriginal racial origin (adjusted odds ratio 1.78; 95% CI: 1.45,2.19), obesity, age and absence of a recorded dialysate : plasma creatinine ratio (D/P creatinine) measurement. Aboriginal racial origin was also associated with a shorter median time to first peritonitis (9.9 vs 19.3 months, P < 0.05), which remained statistically significant in a multivariate Cox proportional hazards model (adjusted hazard ratio 1.76; 95% CI: 1.47,2.11, P < 0.05). Conclusion: Aboriginal and obese PD patients have a higher rate of peritonitis and a shorter time to first peritonitis, independent of demographic and comorbid factors. Further investigation of the causes of increased peritonitis risk in Aboriginal patients is needed. [source]


    Increases in peritoneal small solute transport in the first month of peritoneal dialysis predict technique survival

    NEPHROLOGY, Issue 6 2004
    KATHRYN J WIGGINS
    SUMMARY: Background: Peritoneal transport of small solutes generally increases during the first month of peritoneal dialysis (PD). The aim of this study was to prospectively evaluate the ability of the peritoneal equilibration test (PET), carried out 1 and 4 weeks after the commencement of PD, to predict subsequent technique survival. Methods: Fifty consecutive patients commencing PD at the Princess Alexandra Hospital between 1 February 2001 and 31 May 2003 participated in the study. Paired 1 week and 1 month PET data were collated and correlated with subsequent technique survival. Results: A significant increase was observed in the dialysate : plasma creatinine ratio at 4 h (D/P Cr) between 1 and 4 weeks after the onset of PD (0.55 ± 0.12 vs 0.66 ± 0.11, P < 0.001). Mean death-censored technique survival was superior in patients who experienced ,20% rise in D/P Cr during the first month of PD compared with those who did not (2.3 ± 0.2 vs 1.6 ± 0.2 years, P < 0.05). Using a multivariate Cox proportional hazards model analysis, the significant independent predictors of death-censored technique survival were an increase in D/P Cr of greater than 20% during the first month (adjusted hazard ratio [HR] 0.20, 95% CI 0.05,0.75), the absence of diabetes mellitus, the absence of ischaemic heart disease, body mass index and baseline peritoneal creatinine clearance. Conclusions: A 20% or greater rise in D/P Cr during the first month of commencing PD is independently predictive of PD technique survival. Further investigations of the mechanisms underlying this phenomenon are warranted. [source]


    Increase of matrix metalloproteinase-2 in dialysate of rat sclerosing encapsulating peritonitis model

    NEPHROLOGY, Issue 4 2002
    Ichiro HIRAHARA
    SUMMARY: Sclerosing peritonitis (SP) and sclerosing encapsulating peritonitis (SEP) are serious complications of continuous ambulatory peritoneal dialysis (CAPD). the mortality rate of SP/SEP is extremely high. It is important to clarify the mechanism of progression of SP/SEP, and to prevent this complication. We prepared an animal model of SEP by intraperitoneal administration of chlorhexidine gluconate (CHX) using male Sprague-Dawley rats. Dialysate drained from these animals was analysed by gelatin zymography. In this animal model of SEP, fibrous peritoneal thickening accompanied by cellular infiltration and peritoneal adhesion, were observed. Four of six rats presented with a so-called abdominal cocoon. an increase of peritoneal absorption of glucose was also confirmed. Zymographic analysis revealed that the matrix metalloproteinase-2 (MMP-2) level was high in the dialysate from the animal model, although MMP-9 was hardly detected. From these results, the MMP-2 level in drained dialysate was considered to increase in SP/SEP. Matrix metalloproteinase-2 might be associated with the progression of SP/SEP. [source]


    A direct injection high-throughput liquid chromatography tandem mass spectrometry method for the determination of a new orally active ,v,3 antagonist in human urine and dialysate

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2003
    Wei Zeng
    A generic high-throughput liquid chromatography (HTLC) tandem mass spectrometry (MS/MS) assay for the determination of compound I in human urine and dialysate (hemodialysis) was developed and validated. By using the HTLC on-line extraction technique, sample pretreatment was not necessary. The sample was directly injected onto a narrow bore large particle size extraction column (50,×,1.0,mm, 60,,m) where the sample matrix was rapidly washed away using a high flow rate (5,mL/min) aqueous mobile phase while analytes were retained. The analytes were subsequently eluted from the extraction column onto an analytical column using an organic-enriched mobile phase prior to mass spectrometric detection. The analytes were then eluted from the analytical column to the mass spectrometer for the determination. The linear dynamic range was 2.0,6000,ng/mL for the urine assay and 0.1,300,ng/mL for the dialysate assay. Intraday accuracy and precision were evaluated by analyzing five replicates of calibration standards at all concentrations used to construct the standard curve. For the urine assay, the precision (RSD%, n,=,5) ranged from 1.9 to 8.0% and the accuracy ranged from 87.8 to 105.2% of nominal value. For the dialysate assay, the precision (RSD%, n,=,5) ranged from 1.1 to 10.0% and the accuracy from 94.5 to 105.2% of nominal value. In-source fragmentation of the acyl glucuronide metabolite (compound III) did not interfere with the determination of parent compound I. The developed HTLC/MS/MS methodology was specific for compound I in the presence of compound III. Column life-time is increased and sample analysis time is decreased over traditional reversed-phase methods when direct injection assays for urine and dialysate are coupled with the technology of HTLC. Copyright © 2003 John Wiley & Sons, Ltd. [source]


    Treatment of Thyrotoxic Crisis With Plasmapheresis and Single Pass Albumin Dialysis: A Case Report

    ARTIFICIAL ORGANS, Issue 2 2010
    Sebastian Koball
    Abstract Thyrotoxic crisis (thyroid storm) is a life-threatening condition. Standard therapy is based on thiamazole, prednisolone, and nonselective beta-blockers. Extracorporeal plasmapheresis is an additional tool for removing circulating thyroxine in patients who do not respond quickly to conventional standard therapy. As thyroxine can be bound by albumin, the aims of the present therapy report were to investigate the potential of extracorporeal single-pass albumin dialysis (SPAD) to remove thyroid hormones and to compare it with plasmapheresis. A 68-year-old female with thyrotoxic crisis refractory to conventional therapy underwent two sessions of plasmapheresis without clinical response. For the treatment dose to be increased, the patient was then treated with a modified continuous veno-venous hemodialysis with a dialysate containing 4% of human serum albumin (SPAD) intended to bind and remove thyroxines continuously. In total, the patient received three sessions of plasmapheresis and four SPAD treatments. Thyroxine levels were detected in the patient and in exchanged plasma or albumin dialysate, respectively, to calculate the amount removed. The main finding was that SPAD treatments were tolerated well by the patient. Due to continuous approach, SPAD sessions removed more thyroid hormone than plasmapheresis did, resulting in the improvement of the clinical status of the patient (reduction of heart rate and catecholamine dosage), which enabled bridging the patient to thyroidectomy as the ultimate surgical treatment. This is the first clinical report of the use of albumin dialysis in thyroid storm. SPAD represents a safe and efficient alternative to plasmapheresis as it can be performed continuously in this critical condition. [source]


    An Animal Study of a Newly Developed Skin-Penetrating Pad and Covering Material for Catheters to Prevent Exit-Site Infection in Continuous Ambulatory Peritoneal Dialysis

    ARTIFICIAL ORGANS, Issue 12 2009
    Masato Aoyama
    Abstract Because currently available peritoneal dialysis catheters are not sufficiently biocompatible with the skin and subcutaneous tissue at the site of penetration, exit-site infection due to pericatheter pocket formation caused by epidermal downgrowth over a long period of time has increasingly become a problem. We developed a new, biocompatible, segmented polyurethane porous material and devised a novel skin-penetrating pad, the form and material of which we optimized for application in peritoneal dialysis catheters. For the extent of tissue ingrowth into this porous material to be examined, test materials with different pore diameters were inserted into hollow silicone tubes and implanted in the subcutaneous tissue of a goat. Four weeks later, the tubes were extracted, and, after the extent of granulation tissue ingrowth was measured, histopathological evaluation was made. Our novel skin-penetrating pad has three disklike layers of the segmented polyurethane material with different pore sizes, into the center of which a polyurethane catheter is inserted. These pads were implanted in the skin of a goat and clinically observed over a 2-year period, after which they were extracted and histopathologically analyzed. In accordance with actual clinical procedures, a commercial CAPD catheter equipped with our skin-penetrating pad was left indwelling in a goat for 4 months, and the performance of the pad was evaluated after repeated periodic infusion and drainage of the dialysate in and out of the abdominal cavity. There was no inflammation of the ingrown tissue in the pores of the segmented polyurethane material as well as the surrounding tissue, which indicated favorable tissue biocompatibility. The extent of tissue ingrowth was greater as the pore size of the material was larger, and the tissue tended to be mature, mainly consisting of collagenous fibers. The skin-penetrating pad using the porous material, of which tissue ingrowth was thus optimized, tightly adhered to the goat skin throughout the 2-year experimental period without any special wound care such as cleansing or disinfection. The performance of the skin-penetrating pad was similarly favorable when attached to a commercial continuous ambulatory peritoneal dialysis catheter. The newly developed segmented polyurethane porous material had excellent tissue biocompatibility and tissue ingrowth. The skin-penetrating pad devised by using this porous material did not cause epidermal downgrowth, suggesting that it may be effective for the prevention of exit-site infection. [source]


    Model-Based Analysis of Potassium Removal During Hemodialysis

    ARTIFICIAL ORGANS, Issue 10 2009
    Andrea Ciandrini
    Abstract Potassium ion (K+) kinetics in intra- and extracellular compartments during dialysis was studied by means of a double-pool computer model, which included potassium-dependent active transport (Na-K-ATPase pump) in 38 patients undergoing chronic hemodialysis. Each patient was treated for 2 weeks with a constant K+ dialysate concentration (K+CONST therapy) and afterward for 2 weeks with a time-varying (profiled) K+ dialysate concentration (K+PROF therapy). The two therapies induced different levels of K+ plasma concentration (K+CONST: 3.71 ± 0.88 mmol/L vs. K+PROF: 3.97 ± 0.64 mmol/L, time-averaged values, P < 0.01). The computer model was tuned to accurately fit plasmatic K+ measured in the course and 1 h after K+CONST and K+PROF therapies and was then used to simulate the kinetics of intra- and extracellular K+. Model-based analysis showed that almost all the K+ removal in the first 90 min of dialysis was derived from the extracellular compartment. The different K+ time course in the dialysate and the consequently different Na-K pump activity resulted in a different sharing of removed potassium mass at the end of dialysis: 56% ± 17% from the extracellular compartment in K+PROF versus 41% ± 14% in K+CONST. At the end of both therapies, the K+ distribution was largely unbalanced, and, in the next 3 h, K+ continued to flow in the extracellular space (about 24 mmol). After rebalancing, about 80% of the K+ mass that was removed derived from the intracellular compartment. In conclusion, the Na-K pump plays a major role in K+ apportionment between extracellular and intracellular compartments, and potassium dialysate concentration strongly influences pump activity. [source]