Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ultrafiltration”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources
PubMed2006

The role of ultrafiltration in the management of heart failure.

In the United States, 90% of one million annual hospitalizations for heart failure are due to symptoms of volume overload. Hypervolemia contributes to heart failure progression and mortality. Treatment guidelines recommend that therapy for patients with heart failure be aimed at achieving euvolemia. Intravenous loop diuretics induce a rapid diuresis that reduces lung congestion and dyspnea. However, loop diuretics' effectiveness declines with repeated exposure. Unresolved congestion may contribute to high re-hospitalization rates. Furthermore, loop diuretics may be associated with increased morbidity and mortality due to deleterious effects on neurohormonal activation, electrolyte balance, and cardiac and renal function. Ultrafiltration is an alternative method of sodium and water removal, which safely improves hemodynamics in patients with heart failure. Application of this technology has been limited by the need for high flow rates, large extracorporeal blood volumes, and large-bore central venous catheters. A modified ultrafiltration device has overcome these limitations. Ultrafiltration may be a safe and effective alternative to intravenous diuretics in the treatment of decompensated heart failure.

Journal Article↗
PubMed2005

Ultrafiltration versus usual care for hospitalized patients with heart failure: the Relief for Acutely Fluid-Overloaded Patients With Decompensated Congestive Heart Failure (RAPID-CHF) trial.

OBJECTIVES: The purpose of this research was to assess the safety and efficacy of ultrafiltration (UF) in patients admitted with decompensated congestive heart failure (CHF). BACKGROUND: Ultrafiltration for CHF is usually reserved for patients with renal failure or those unresponsive to pharmacologic management. We performed a randomized trial of UF versus usual medical care using a simple UF device that does not require special monitoring or central intravenous access. METHODS: Patients admitted for CHF with evidence of volume overload were randomized to a single, 8 h UF session in addition to usual care or usual care alone. The primary end point was weight loss 24 h after the time of enrollment. RESULTS: Forty patients were enrolled (20 UF, 20 usual care). Ultrafiltration was successful in 18 of the 20 patients in the UF group. Fluid removal after 24 h was 4,650 ml and 2,838 ml in the UF and usual care groups, respectively (p = 0.001). Weight loss after 24 h, the primary end point, was 2.5 kg and 1.86 kg in the UF and usual care groups, respectively (p = 0.240). Patients tolerated UF well. CONCLUSIONS: The early application of UF for patients with CHF was feasible, well-tolerated, and resulted in significant weight loss and fluid removal. A larger trial is underway to determine the relative efficacy of UF versus standard care in acute decompensated heart failure.

Adrenergic beta-Antagonists↗
PubMed2004

Metal ions removal from wastewater or washing water from contaminated soil by ultrafiltration-complexation.

In the present paper a process for removal of ions from wastewater or from washing water of contaminated soil by using the weakly basic water-soluble polymer polyethylenimine (PEI) as chelating agent and the Cu(2+) ion as model in combination with an ultrafiltration process was investigated. The complexing agent was preliminarily tested to establish the best operative conditions of the process. Next, ultrafiltration tests by using five different membranes were realised to check membrane performance like flux and rejection. Finally, the possibility for recovering and recycling the polymer was tested in order to obtain an economically sustainable process. Obtained results showed that complexation conditions depends on pH: indeed, at a pH>6 PEI-Cu(2+) complexes are formed, while at pH<3 the decomplexation reaction takes place. Saturation condition is 0.333 mg Cu(2+)/mg PEI, meaning a ratio PEI/Cu(2+)=3(w/w). UF tests showed good results using the PAN 40 kDa membrane reaching an average copper concentration in the permeate of 2 mg/l and a flux of 135.4 and 156.5l/h.m(2) at 2 and 4 bar, respectively. Metal rejection, permeate flow rate, and possibility to regenerating and recycling the polymer makes the polymer-assisted ultrafiltration process (PAUF) very interesting for metal ion removal from waters.

Chelating Agents↗
PubMed2003

Application of ultrafiltration and stable isotopic amendments to field studies of mercury partitioning to filterable carbon in lake water and overland runoff.

Results from pilot studies on colloidal phase transport of newly deposited mercury in lake water and overland runoff demonstrate that the combination of ultrafiltration, and stable isotope amendment techniques is a viable tool for the study of mercury partitioning to filterable carbon. Ultrafiltration mass balance calculations were generally excellent, averaging 97.3, 96.1 and 99.8% for dissolved organic carbon (DOC), total mercury (Hg(T)), and methylmercury (MeHg), respectively. Sub nanogram per liter quantities of isotope were measurable, and the observed phase distribution from replicate ultrafiltration separations on lake water agreed within 20%. We believe the data presented here are the first published colloidal phase mercury data on lake water and overland runoff from uncontaminated sites. Initial results from pilot-scale lake amendment experiments indicate that the choice of matrix used to dissolve the isotope did not affect the initial phase distribution of the added mercury in the lake. In addition there was anecdotal evidence that native MeHg was either recently produced in the system, or at a minimum, that this 'old' MeHg partitions to the same subset of DOC that binds the amended mercury. Initial results from pilot-scale overland runoff experiments indicate that less than 20% of newly deposited mercury was transported in the filterable fraction (<0.7 microm). There is some indication of colloidal phase enrichment of mercury in runoff compared to the phase distribution of organic carbon, but the mechanism of this enrichment is unclear. The phase distribution of newly deposited mercury can differ from that of organic carbon and native mercury, suggesting that the quality of the carbon (available ligands), not the quantity of carbon, regulates partitioning. Further characterization of DOC is needed to clarify the underlying mechanisms.

Biological Availability↗
PubMed2001

Circulatory response to fluid overload removal by extracorporeal ultrafiltration in refractory congestive heart failure.

OBJECTIVES: The goal of this study was to investigate the hemodynamic and circulatory adjustments to extracorporeal ultrafiltration (UF) in refractory congestive heart failure (rCHF). BACKGROUND: In rCHF, UF allows clinical improvement and restores diuretic efficacy. However, in the course of a UF session, patients are exposed to rapid variations of body fluid composition so that, as fluid is withdrawn from the intravascular compartment, hypotension or even shock could occur. METHODS: In 24 patients with rCHF undergoing UF, we measured, after every liter of plasma water removed, hemodynamics, blood gas analysis (in both systemic and pulmonary arteries), plasma volume changes (PV) and plasma refilling rate (PRR). The PV and PRR were calculated by considering hematocrit and ultrafiltrate volume. RESULTS: In all patients, UF was performed safely, without side effects or hemodynamic instability (ultrafiltrate = 4,880 +/- 896 ml). Mean right atrial, pulmonary artery and wedge pressures progressively reduced during the procedure. Cardiac output increased at the end of the procedure and, to a greater extent, 24 h later, in relation to the increase of stroke volume. Heart rate and systemic vascular resistance did not increase, and other peripheral biochemical parameters did not worsen during UF. Intravascular volume remained stable throughout the entire duration of the procedure, indicating that a proportional volume of fluid was refilled from the congested parenchyma. CONCLUSIONS: In patients with rCHF, subtraction of plasma water by UF is associated with hemodynamic improvement. Fluid refilling from the overhydrated interstitium is the major compensatory mechanism for intravascular fluid removal, and hypotension does not occur when plasma refilling rate is adequate to prevent hypovolemia.

Aged↗
PubMed1998

Effect of veno-venous ultrafiltration on myocardial performance immediately after cardiac surgery in children. A prospective randomized study.

OBJECTIVES: This study sought to evaluate the effects of veno-venous ultrafiltration on myocardial contractility in children undergoing cardiopulmonary bypass (CPB) for repair of congenital heart defects. BACKGROUND: Ultrafiltration (UF) is currently used to diminish postoperative fluid accumulation following CPB in children. Previous reports indicate improvement in hemodynamics immediately after UF, but the mechanism of its action is unknown. METHODS: Twenty-three patients (ages 2 months to 9.1 years; 13 males, 10 females) underwent UF for 10 min after CPB. Twelve patients underwent UF immediately after CPB (Group A). They were studied: (1) before and (2) after CPB, (3) after UF, and (4) 10 min after UF. Eleven patients underwent UF 10 min after CPB (Group B). They were studied: (1) before and (2) after CPB, (3) after a 10-min delay before UF, and (4) after UF. Contractility was determined by the difference in the observed and predicted velocity of circumferential fiber shortening for the measured wall stress, using transesophageal echocardiography. Left ventricular wall thickness was also measured. RESULTS: There was significant improvement in contractility after UF in both groups (mean+/-SD, Group A: -0.28+/-0.13 to -0.01+/-0.21 circ/s, p < 0.05; Group B: -0.26+/-0.16 to -0.11+/-0.17 circ/s, p < 0.05). Myocardial thickness to cavity dimension decreased in both groups following UF (Group A: 0.19+/-0.04 to 0.14+/-0.03, p < 0.05; Group B: 0.18+/-0.04 to 0.14+/-0.03, p < 0.05). CONCLUSIONS: UF improves hemodynamics by improving contractility and possibly by reducing myocardial edema in children following cardiac surgery. Enhanced patient outcome after ultrafiltration may in part be due to these changes.

Cardiopulmonary Bypass↗
PubMed2000

Modified ultrafiltration lowers adhesion molecule and cytokine levels after cardiopulmonary bypass without clinical relevance in adults.

OBJECTIVE: Cardiac surgery with cardiopulmonary bypass (CPB) results in expression of cytokines and adhesion molecules (AM) with subsequent inflammatory response. The purpose of the study was to evaluate the clinical impact of modified ultrafiltration (MUF) and its efficacy in reducing cytokines and AM following coronary artery bypass grafting (CABG) in adults. METHODS: A prospective randomized study of 97 patients undergoing elective CABG was designed. Fifty patients were operated on using normothermic and 47 patients using hypothermic CPB. The normothermic group was subdivided into a group with modified ultrafiltration (n = 30) and a group without MUF (n = 20). In the hypothermic group 30 patients received MUF compared to 17 patients serving as controls. MUF was instituted after CPB for 15 min through the arterial and venous bypass circuit lines. Cytokines (IL-6, IL-8, TNF-alpha, IL-2R) and adhesion molecules (sE-selectin, sICAM-1) were measured preoperatively, pre-MUF, in the ultrafiltrate, 24 h, 48 h and 6 days after surgery by chemiluminescent enzyme immunometric assay or enzyme-linked immunosorbent assay (ELISA). Clinical parameters were collected prospectively until discharge. RESULTS: In all patients AM and cytokines were significantly elevated after normothermic and hypothemic CPB. AM and cytokines were significantly higher in hypothermia compared to normothermia. In hypothermic CPB sE-selectin was decreased after 24 h by 37% (P < 0.0063) and by 40% (P < 0.0027) after 48 h postoperatively. ICAM-1 was reduced by 43% (P < 0.0001) after 24 h and by 60% (P < 0.0001) after 6 days. Similar results were seen in cytokines with reduction up to 60% after 24 h. Changes after 48 h were noticeable but not significant. Reduction of AM and cytokines after normothermic CPB was minimal. Neither in normothermia, nor in hypothermia has sIL-2R been effectively removed from the circulation. There were no significant differences in the clinical variables between the patients with or without MUF. CONCLUSION: AM and cytokines are significantly elevated after hypothermic CPB compared to normothermic CPB. MUF led to a significant reduction in cytokine and AM levels after hypothermic CPB, except for IL-2R. MUF showed minimal effect in normothermia. We conclude that MUF is an efficient way to remove cytokines and AM. However, we were unable to demonstrate any significant impact of MUF in outcome of adults after elective CABG.

Adult↗
PubMed1998

Use of modified ultrafiltration after repair of congenital heart defects.

The use of cardiopulmonary bypass (CPB) for repair of congenital heart defects exposes children to extremes of hemodilution and hypothermia. Exposure of blood to the foreign surfaces of the oxygenator and bypass circuit initiates a systemic inflammatory response. Adverse effects of CPB include increased capillary permeability and increased total body water (TBW), which often results in tissue edema and multiple organ dysfunction. A variety of techniques have been developed for reversing tissue edema and hemodilution after CPB, including ultrafiltration during CPB, postoperative peritoneal dialysis, postoperative continuous arterial venous hemofiltration, and aggressive use of diuretics. A technique termed modified ultrafiltration (MUF) has been developed at the Hospital for Sick Children in London. Unlike conventional ultrafiltration, MUF is performed in the immediate post-CPB period and removes excess water from the patient as well as provides a method of salvaging blood from the circuit. MUF has been shown to modulate the inflammatory response to CPB by removing inflammatory mediators including interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF). A prospective randomized trial of MUF showed improved hemodynamics with a reduction in TBW and decreased need for blood transfusion when compared with nonfiltered controls. MUF has been shown to improve left ventricular systolic function after CPB, resulting in increased systolic blood pressure and cardiac index. In a recent study, use of MUF significantly reduced the incidence of pleural effusions after cavopulmonary connection and the Fontan procedure. MUF is a useful adjunct to CPB in children and significantly decreases perioperative morbidity. Copyright 1998 by W.B. Saunders Company

Journal Article↗
PubMed2005

Dendrimer enhanced ultrafiltration. 1. Recovery of Cu(II) from aqueous solutions using PAMAM dendrimers with ethylene diamine core and terminal NH2 groups.

This article discusses the feasibility of using dendrimer enhanced ultrafiltration (DEUF)to recover Cu(II) from aqueous solutions. Building upon the results of fundamental investigations of Cu(II) binding to PAMAM dendrimers with ethylenediamine (EDA) core and terminal NH2 groups, we combine (i) dead-end ultrafiltration (UF) experiments with (ii) atomic force microscopy (AFM) characterization of membrane fouling to assess the feasibility of using DEUF to recover Cu(II) from aqueous solutions. On a mass basis, the Cu(II) binding capacities of the EDA core PAMAM dendrimers are much larger and more sensitive to solution pH than those of linear polymers with amine groups. The dendrimer-Cu(II) complexes can be efficiently separated from aqueous solutions by ultrafiltration. The metal ion laden dendrimers can be regenerated by decreasing the solution pH to 4.0; thus enabling the recovery of the bound Cu(II) ions and recycling of the dendrimers. The UF measurements and AFM characterization studies show that EDA core PAMAM dendrimers with terminal NH2 groups have very lowtendency to foul the commercially available regenerated cellulose (RC) membranes evaluated in this study. The overall results of these experiments suggest that DEUF is a promising process for recovering metal ions such as Cu(II) from aqueous solutions.

Cellulose↗
PubMed2004

Ultrafiltration in the treatment of severe congestive heart failure.

BACKGROUND: Fluid removal remains a fundamental goal in the treatment of congestive heart failure (CHF). Vacuum ultrafiltration, hemodialysis, or a combination of both was used in patients with severe CHF (NYHA class IV), severe edema, and insensitivity to pharmacological treatment with diuretics. METHODS: The aim of the study was to remove the overload fluid in eighteen patients, 13 men and 5 women, aged 38 to 83, with a man age of 66 years with intractable congestive heart failure. All patients were hospitalized because of severe congestive heart failure and did not respond to treatment with intravenous administration of a high dose of diuretics and positive inotropic agents. They thus underwent vacuum ultrafiltration (1 to 27 sessions) while in 4 of them hemodialysis was also performed because of high serum creatinine levels (over 4 mg/dl). Subclavian catheters were used in all patients and arteriovenous fistula was later performed in 2, because of the need for long term treatment. The average fluid removed was 2 L per session and the total fluid removed ranged from 4 to 29 L. RESULTS: Fourteen of the 18 patients (78%) showed significant improvement in their clinical status. Ten patients (56%) had a short term improvement but expired after 7 to 107 days of hospitalization. Four patients (22%) died after only one session of dialysis and 4 patients (22%) recovered after 8 to 23 dialysis sessions and were discharged from hospital. CONCLUSION: The majority of patients with severe chronic CHF which is intractable to conventional therapy including intravenous diuretics and inotropes improve by the use of ultrafiltration. However, a limited proportion of them survive to be discharged from the hospital.

Adult↗
PubMed2000

Role of glomerular ultrafiltration of growth factors in progressive interstitial fibrosis in diabetic nephropathy.

BACKGROUND: The present in vivo and in vivo experiments were performed to test the hypothesis that in rats with glomerular proteinuria, the bioactive growth factors transforming growth factor-beta (TGF-beta) and hepatocyte growth factor (HGF) are ultrafiltered into tubular fluid, can interact with respective receptors in apical tubular cell membranes, increase the expression and basolateral secretion of C-C-chemokines, which interact with cells in the renal interstitium and indirectly cause myofibroblasts to increase the expression of extracellular matrix proteins. METHODS: HGF and TGF-beta were measured by Western blot and bioassay in glomerular ultrafiltrate that was collected by nephron micropuncture from rats with diabetic nephropathy and control rats. Proximal tubular and collecting duct cells were incubated with diluted proximal tubular fluid or recombinant human HGF (rhHGF) or rhTGF-beta and expression of C-C-chemokines was measured by RT-PCR and ELISA. Interactions of tubular cell chemokines with macrophages and indirectly with myofibroblasts were also examined using cell culture models. RESULTS: In rats with glomerular proteinuria due to diabetic nephropathy mature, bioactive HGF as well as active and latent TGF-beta were detected in early proximal tubular fluid. Specific HGF- and TGF-beta type II receptors were expressed in apical tubular membranes more in diabetic compared to control rats. Incubation of cultured mouse proximal tubular cells (mPTC) or medullary collecting duct cells (mIMCD-3) with diabetic rat proximal tubular fluid increased MCP-1 and RANTES mRNA levels as well as secreted peptide up to threefold. In contrast, high glucose (450 mg/dL), bovine serum albumin (BSA) or rat albumin (each at 100 micrograms/mL) or 10 nmol/L insulin-like growth factor-I (IGF-I; which was also present in glomerular ultrafiltrate in rats with diabetic nephropathy) did not affect expression of these chemokines. Recombinant human TGF-beta as well as rhHGF each increased MCP-1 and RANTES mRNA as well as peptide levels several-fold. In cultured macrophages MCP-1 raised the secretion of TGF-beta, which in turn increased the expression of collagen type I and III as well as fibronectin in renal interstitial myofibroblasts about 2.5 to 4-fold. CONCLUSIONS: Proteinuria-induced progressive renal interstitial fibrosis may be caused by glomerular ultrafiltration of high molecular weight bioactive growth factors, HGF and TGF-beta, which "activate" tubular cells through apical membranes. These apical signals are translated into basolateral events that are recognized by cells in the interstitium, such as the basolateral secretion of the C-C-chemokines MCP-1 and RANTES, which may (via macrophages) stimulate interstitial myofibroblasts, and thus lead to accumulation of extracellular matrix proteins and progressive interstitial fibrosis.

Animals↗
PubMed2002

The complex role of nitric oxide in the regulation of glomerular ultrafiltration.

The complex role of nitric oxide in the regulation of glomerular ultrafiltration. Nitric oxide is an important neurohumoral modulator of glomerular ultrafiltration and renal hemodynamics. Multiple nitric oxide synthase (NOS) isoforms are present within the kidney. However, it is difficult to discern which NOS is most active from prior studies using non-selective NOS blockers. It is recently apparent that NOS activity is important to the activity of tubuloglomerular feedback (TGF) systems, systems that relate tubular reabsorption to the regulation of glomerular ultrafiltration. Neuronal (nNOS) or brain NOS (bNOS; NOS I) is present within the macula densa, the sensing element of TGF systems. Inhibition of NOS activity and specifically bNOS enhances TGF activity. The TGF system also adapts temporally and these events appear to be dependent upon up-regulation of activity of bNOS within the kidney. Temporal adaptation occurs within one to three hours whereby activation of TGF is followed by a gradual return of the glomerular filtration rate (GFR) and renal blood flow toward normal levels. After 24 hours of benzolamide treatment and withdrawal of this agent, glomerular filtration actually increases to supranormal levels and this is prevented by inhibition of bNOS activity. Factors regulating bNOS activity have not been fully clarified. We have recently observed N-methyl-d-aspartate (NMDA) receptors within the kidney that, when inhibited, result in major reductions in renal blood flow and GFR, suggesting an important role for the NMDA receptor in regulation of renal hemodynamics. Future studies will determine whether NMDA receptor is also an important regulator of bNOS activity and the TGF system.

Animals↗
PubMed2000

Modified ultrafiltration improves carbon dioxide removal after cardiopulmonary bypass in infants.

Little is known about the role of modified ultrafiltration in ameliorating the adverse effects of the cardiopulmonary bypass on pulmonary function in infants. Twenty-nine nonrandomized consecutive infants (<12 months of age) who underwent unrestrictive ventricular septal defect closure between 1995 and 1998 were included in this study. Down's syndrome was associated in 9 patients. The actual ventilator settings were highly homogeneous among all patients and each time point in the study. Fourteen infants received modified ultrafiltration after the discontinuation of cardiopulmonary bypass. Fifteen untreated patients served as the control group. Correlates of cardiac and pulmonary functions for both groups were compared. The arterial carbon dioxide tension in the experimental group was significantly lower than in the control group from 20 to 240 min after bypass. Arterial oxygenation and pulmonary arterial pressure were similar in the 2 groups. Modified ultrafiltration improves carbon dioxide removal after cardiopulmonary bypass in infants. This may potentially convey a beneficial impact on hemodynamics.

Analysis of Variance↗
PubMed2004

The benefits of continuous ultrafiltration in pediatric cardiac surgery.

BACKGROUND: Systemic inflammatory response and capillary leak syndrome, caused by extracorporeal circulation, have negative effects on the function of vital organs during the postoperative period. Modified ultrafiltration (MUF) has been developed as an alternative method to reduce the detrimental effects of cardiopulmonary bypass. The aim of this prospective, randomized study is to analyze the effects of MUF in a pediatric population undergoing congenital cardiac surgery. METHODS: Twenty-seven patients who underwent open-heart surgery at our institution were included in this prospective study. They were randomized into two groups as follows: Group I (n=14) of conventional ultrafiltration during bypass and Group II (n=13) receiving both conventional and modified ultrafiltration during and after the cessation of the bypass, respectively. The amount of prime volume, postoperative chest drain loss, transfusion requirements, hemodynamical parameters, duration of mechanical ventilatory support, and length of intensive care unit stay were compared between the two groups. During the postoperative period, the concentrations of hematological, biochemical and inflammatory parameters were also compared by analyzing the blood samples obtained at various time points. RESULTS: MUF resulted in a significant increase in hemoglobin, hematocrit and platelet levels, and significantly reduced the amount of chest tube output and transfused blood and blood products. MUF also shortened the duration of postoperative mechanical ventilatory support, length of the intensive care unit stay and improved postoperative hemodynamical parameters. During the early postoperative hours, IL-8 is significantly reduced in patients undergoing MUF, however, the concentrations of IL-8 were similar in both groups at the end of 24 h. CONCLUSIONS: MUF decreases the duration of mechanical ventilatory support, the length of intensive care unit stay, the need for blood transfusion and improves postoperative hemodynamics. It is associated with increased levels of hemoglobin, hematocrit and platelets. We can conclude that MUF attenuates the inflammatory response by decreasing the levels of inflammatory mediators.

Blood Pressure↗
PubMed1992

Clustered bacteremias in a hemodialysis unit: cross-contamination of blood tubing from ultrafiltrate waste.

OBJECTIVE: To determine the cause of clustered bacteremias occurring among chronic hemodialysis patients. DESIGN: A retrospective investigation of clinical and laboratory records with direct observation of dialysis facilities and technique. Bacterial blood isolates were identified and compared with environmental isolates. SETTING: The 11-station chronic hemodialysis unit that serves approximately 50 patients in a 450-bed military hospital. PATIENTS: Hemodialysis unit patients with aerobic gram-negative bacillus or Enterococcus casseliflavus blood isolates between April 1988 and February 1990. RESULTS: The recovery and species identification of the unique isolate, E casseliflavus, from 2 index cases of bacteremia in February 1990 helped identify the cluster and demonstrated its protracted course. Dialysis blood tubing was contaminated with ultrafiltrate waste during dialyzer setup. INTERVENTION: Bacteremias were controlled by halting the practice of attaching the venous tubing directly to a waste container while priming the membrane, by emphasizing glove changes and handwashing after contact with ultrafiltrate waste and by daily decontamination of ultrafiltrate waste bags. CONCLUSIONS: We recommend that other hemodialysis units institute these interventions.

Bacteremia↗
PubMed1992

Potentiation of azithromycin activity against Escherichia coli by human serum ultrafiltrate.

In this study we investigated the influence of serum ultrafiltrate on the activities of azithromycin, other macrolides and unrelated antibiotics against Escherichia coli. In the presence of serum ultrafiltrate the MIC of azithromycin was decreased by 10-fold. The activities of erythromycin and roxithromycin were also enhanced, although to a lesser extent. The potentiation of activity was inhibited by divalent cations and by pre-treatment of the ultrafiltrate with trypsin. Potentiation of azithromycin activity was associated with a pH-independent, early increase in bactericidal activity and inhibition of bacterial metabolism. We postulate that low molecular weight proteinaceous components of normal human serum interact with azithromycin and other macrolides to alter the susceptibility of Gram-negative bacteria to the antibiotics, possibly through increased macrolide penetration across the bacterial cell membrane permeability barriers.

Azithromycin↗
PubMed2005

Effects on inflammatory and nutritional markers of haemodiafiltration with online regeneration of ultrafiltrate (HFR) vs online haemodiafiltration: a cross-over randomized multicentre trial.

BACKGROUND: HFR [double chamber haemodiafiltration (HDF) with reinfusion of regenerated ultrafiltrate] is a novel dialytic method which combines the processes of diffusion, convection and adsorbance. In this technique an adsorbent cartridge of resin and charcoal may regenerate the ultrafiltrate suggesting its use as an endogenous substitution fluid. The aim of this multicentre randomized cross-over study was to compare HFR to online HDF in terms of inflammatory and nutritional parameters. METHODS: After a 1 month run-in period of standard bicarbonate dialysis (HD) with a synthetic membrane, 25 chronic dialytic patients were randomized (A-B or B-A) to be treated by HFR (A) with a two-chamber filter (SG 8 Plus - high permeability Polysulphone HF 0.7 m2 + SMC 1.95 sqm; Bellco, Mirandola, Italy) or by online sterile bicarbonate HDF. Each study period of 4 months was separated by 1 month of HD and the entire length of the study was 10 months. CRP levels were measured by a highly sensitive nephelometric assay (Dade, Behring) with a sensitivity of 0.1 microg/ml. Cytokine concentrations were determined by EIA [Interleukin (IL) 6, Biosource, USA and IL-10 Bender MED-Systems, Vienna]. The sensitivity thresholds were < 5 pg/ml for IL-6 and < 8 pg/ml for IL-10. Serum leptin was determined with a ELISA method (Biosource, USA). All parameters were determined monthly in patients starting a midweek dialytic session. RESULTS: Plasma CRP and IL-6 were significantly reduced during the 4 months of HFR and HDF: CRP from 8.0 +/- 3.2 to 5.6 +/- 3.4 mg/l with HFR (P < 0.05) and from 9.4 +/- 4.3 to 5.9 +/- 3.9 mg/l with HDF (P < 0.05). IL-6 decreased from 14.8 +/- 6.3 to 10.1 +/- 3.2 with HFR (P < 0.02) and from 12.1 +/- 4.2 to 9.6 +/- 3.7 with HDF (P = ns) with a percentage decrease after 4 months of 32% with HFR vs 21% with HDF. During the 1 month wash-out period with HD, CRP increased from 5.7 +/- 3.6 to 8.7 +/- 3.9 mg/l (P < 0.01) and IL-6 from 10 +/- 3.4 to 13.5 +/- 5.2 pg/ml (P < 0.01). A significant increase in IL-10 was detected either in HFR (from 4.8 +/- 2.1 to 6.89 +/- 1.7 pg/ml) and in HDF (from 3.3 +/- 1.7 to 8.95 +/- 4.3 pg/ml; P < 0.05) after 4 months. No significant variation in serum leptin levels were observed during the study. CRP and IL-6 were highly correlated (r = 0.54; P < 0.001) as was serum albumin and prealbumin (r = 0.39; P < 0.001). Serum albumin was negatively correlated with CRP (r = -0.26; P < 0.01) and IL-6 (r = -0.19; P < 0.05); serum prealbumin was correlated with IL-6 (r = 0.37; P < 0.001) and with CRP (r = 0.24; P < 0.01). CONCLUSIONS: Haemodiafiltration with online regeneration of ultrafiltrate and online HDF are highly biocompatible techniques and no significant difference between HFR and online HDF was observed in terms of reduction of inflammatory markers. Further studies with a longer follow-up are needed to evaluate the clinical relevance of the online endogenous reinfusion to counteract the chronic inflammatory state of the uraemic patient.

Aged↗
PubMedDate not supplied

Reasonably short hemodialysis time can be achieved without ultra-high efficiency dialyzers and without ultrafiltration-controlled delivery systems.

To evaluate the ability to provide short hemodialysis (less than 9 hr per week) without the requirement for costly ultra-high efficiency dialyzers and ultrafiltration control delivery systems, 69 patients maintained on chronic hemodialysis were studied. Standard dialysis was delivered with bicarbonate dialysate, Baxter CF 1211 dialyzers, QB = 300 ml/min, mean time 215 min. The mean KT/V was 1.16. Hemodialysis prescription was changed to maintain the KT/V unchanged. Time was decreased by increasing urea clearance by increasing the QB (400 ml/min in 65 patients, 350 ml/min in 4 patients) and employing the Baxter CF 2308 dialyzer. This produced an increase in urea clearance from 192 ml/min to 256 ml/min, and a decrease in duration of dialysis to 164 min. The CF 2308 dialyzer has an ultrafiltration coefficient of 4 ml/mmHg/hr, which is easily managed without ultrafiltration control equipment. Patients were in the study group for a mean of 176.5 days. The short period of time caused no significant change in blood urea nitrogen, creatinine, potassium, bicarbonate, calcium, phosphorus, hematocrit, or symptomatic hypotension and vomiting. Patient acceptance of the change in hemodialysis time was excellent. Hemodialysis times similar to those reported by others with large experience in shortening hemodialysis time can be achieved in many instances with standard hemodialysis equipment.

Bicarbonates↗