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PubMed1986

Multicenter evaluation of ultrafiltration, dialysis, and thermal coagulation as sample pretreatment methods for the colorimetric determination of paraquat in blood and tissues.

Three methods of sample pretreatment for the rapid colorimetric determination of paraquat were compared: ultrafiltration, dialysis, and thermal coagulation. Spiked autopsy blood and tissue samples were examined in parallel in Groningen and Krakow and some samples were interchanged. All three methods gave recoveries between 87 to 102%; accuracy at the 20-mg/L level was within 10% of the target value and coefficients of variation in the 10 to 60-mg/L range were between 3 to 15%. Determinations in blood and liver in a fatal case of Gramoxone poisoning showed excellent agreement. Because of its reliability, speed, and simplicity, ultrafiltration is the method of choice.

Colorimetry↗
PubMed1986

Loss of propranolol during ultrafiltration in plasma protein binding studies.

A commercial ultrafiltration device was examined for propranolol plasma protein binding studies. A nonspecific loss of free drug resulted in a low recovery in the ultrafiltrate. Use of a rinse filtrate did not completely compensate for this loss. Use of different centrifugal forces indicated the loss was not due to significant membrane rejection of drug. Equilibrating the device with sample for four hours slightly improved the recovery while use of a higher ionic strength buffer had no effect. Propranolol was bound by the membrane, but there was a larger, continuous loss to the o-ring. Results with an alternate commercial device were also unsatisfactory.

Blood Proteins↗
PubMed1987

Protocols for use of ultrafiltration in determination of free ligand concentration and of complexity of ligand/protein interactions.

Analysis of a simple ligand/binding-protein association model predicts a decrease in the percentage of free hormone during ultrafiltration. Re-analysis of the original data validating ultrafiltration in free-ligand determinations (Sophianopoulos et al., Arch Biochem Biophys 1978;187:132-7) confirms this prediction. Binding data indicating a constant percentage of free hormone (Hammond et al., J Biol Chem 1980;255;5023-6) require a more complex ligand-protein interaction model. Application of these procedures to any new ligand system requires measurement of the percentage free, or of free-ligand concentration, as a function of filtration time or volume. The protocol becomes important if values for percentage free are to be accurate.

Chemistry, Clinical↗
PubMed1986

Experimental study on the effects of the extracorporeal ultrafiltration method in advanced congestive heart failure.

The effects of the extracorporeal ultrafiltration method were studied in an experimental canine model of advanced congestive heart failure with mitral regurgitation, coronary artery occlusion and overhydration. With the application of this technique, cardiac output, stroke work, systemic vascular resistance and left ventricular dp/dt increased significantly associated with reduction in the right atrial and left ventricular filling pressures. Serum electrolytes were stable throughout the procedure, and there were significant elevations in serum protein and hematocrit levels. The composition of the ultrafiltrate indicated that excessive extracellular fluid was removed. Five out of seven cardiogenic shock subjects also benefited. The clinical application of this approach using recently developed dialyzers to treat intractable heart failure with overhydration under close hemodynamic monitoring is warranted.

Animals↗
PubMed1985

Rapid measurement of free anticonvulsant drugs by direct liquid chromatography of serum ultrafiltrates.

In this simultaneous assay of unbound phenobarbital, phenytoin, primidone, and carbamazepine, serum ultrafiltrate is prepared by centrifugation in disposable filter units (Centrifree Micropartition System, Amicon Corp.) and injected directly onto a reversed-phase liquid-chromatography column. Drugs in the effluent are detected by absorbance at 210 nm. The measured concentrations were not critically dependent on the exact conditions of ultrafiltration (rotor angle, speed or time of centrifugation, amount of sample filtered). Pooled serum containing all four drugs gave reproducible results in repeated analyses during several days. For comparison we assayed 113 clinical specimens for one or more of these drugs by this method, and for the total (bound plus unbound) concentration of each drug by immunoassay. For each drug there was a nearly linear relationship between the two types of measurements, except for six specimens that had unusually high fractions of unbound drug. This assay appears highly suitable for routine determination of the free, biologically active fraction of anticonvulsant drugs, possibly as an alternative to measurements of total drug concentrations.

Anticonvulsants↗
PubMed1985

Equilibrium dialysis, ultrafiltration, and ultracentrifugation compared for determining the plasma-protein-binding characteristics of valproic acid.

Equilibrium dialysis, ultrafiltration, and ultracentrifugation were compared to determine their reliability and applicability in the study of binding of an anticonvulsant drug, valproic acid, by plasma proteins. We studied drug binding with pooled serum and with solutions of human serum albumin at physiological concentrations. We compared binding characteristics such as number of binding sites, affinity constants, and percent of binding as measured by each method in the therapeutic range for valproic acid. Results by ultracentrifugation differed from those by equilibrium dialysis and ultrafiltration, which agreed reasonably well with each other.

Blood Proteins↗
PubMed1985

Ultrafiltration studies in vitro of serum aluminum in dialysis patients after deferoxamine chelation therapy.

Using gel filtration chromatography, we evaluated aluminum bound to albumin, transferrin, and other plasma proteins in the serum of patients on maintenance hemodialysis. The proportion of dialyzable aluminum, as determined by selective membrane ultrafiltration and flameless atomic absorption spectrometry, increased by more than fourfold on treatment with the metal chelator, deferoxamine. This ultrafiltration technique may prove useful for monitoring the proportion of aluminum mobilized during such therapy.

Aluminum↗
PubMed1979

Isolated ultrafiltration in the treatment of fluid overload in cardiogenic shock.

Dramatic improvement in measured hemodynamic values, arterial blood gas values, and renal function was quickly achieved by the use of isolated ultrafiltration in a patient with cardiogenic shock refractory to medical management. Swift venous access was obtained by femoral catheterization, and the rapid removal of 3,500 mL of ultrafiltrate was well tolerated. This technique may afford another mode of therapy in patients with refractory cardiogenic shock associated with severe volume overload.

Catheterization↗
PubMed1980

Cardiothoracic ratio as a guide to ultrafiltration therapy in dialyzed patients.

This study evaluated the cardiothoracic ratio (CTR) and the roentgenologic heart volume (RHV) as indexes of body fluid retention in 37 uremics on maintenance dialysis therapy. Both indexes related to a highly significant degree with the variations of body fluids balance assessed by the changes in body weights. Cardiomegaly (CTR greater than .500) subsided with adequate ultrafiltration therapy in most patients including those having blood pressure values within the normal range. It is concluded that the measurements of CTR provides an useful guide to ultrafiltration therapy especially in those patients whose blood pressure fails to sense the body fluid retention.

Adult↗
PubMed1984

[Acetate dialysate: responsible for decrease in ultrafiltration in continuous ambulatory peritoneal dialysis].

The authors report the follow up of ultrafiltration in 45 chronic renal patients treated by continuous ambulatory peritoneal dialysis from May 1978 to August 1983. 31 patients have been using acetate buffered dialysate, 14 patients lactate buffered dialysate. Ultrafiltration obtained with acetate fluid has always been less important compared with lactate fluid (p less than 0,001). This decrease has been observed in all the acetate patients and has worsened as a function of duration of treatment, whereas it has only been observed in 14,3% of the lactate-dialysed patients.

Acetates↗
PubMed1983

Acute renal failure treated by slow continuous ultrafiltration. Preliminary report.

We report our initial experience with the use of slow continuous ultrafiltration in the treatment of acute renal failure. Advantages of slow continuous ultrafiltration over conventional hemodialysis are greater blood pressure stability, no need for systemic anticoagulation, augmented fluid input and removal, and enhanced ease of operation. Our results in two patients confirm other reports that this method can be successfully performed in hemodynamically unstable patients with acute renal failure.

Acute Kidney Injury↗
PubMedDate not supplied

[Application of ultrafiltration for concentration and purification of Penicillium vitale catalase].

Various factors are studied for their effect on the ultrafiltration of Penicillium vitale catalase. It is established that acetate cellulose and polyamide membranes may be used for additional purification and deep concentration of native preliminarily purified enzyme solutions. Membranes YAM-300 and YAM-450 are most preferable. At the temperature of 10 degrees C, pressure 0.2 MPa and 100-fold concentration of the catalase solution the enzyme yield at the ultrafiltration stage is 96-100%.

Catalase↗
PubMedDate not supplied

[Use of Vladipore cellulose acetate ultrafiltration membranes for isolation of small peptides].

Retintion of some amino acids and peptides by standard ultrafiltration membranes "Vladipore" was studied. Membranes UAM-30M and UAM-50M may be used for concentration and desalting of peptides containing not less than 3-4 amino acid residues. An increase in NaCl concentration in the samples led to a decrease in the peptide retention coefficient. The ultrafiltration membranes were used for isolation of small peptides from blood, urine and extracts of normal skin, after thermal trauma and irradiation of the tissue.

Amino Acids↗
PubMed1983

[Blood gas and acid-base changes and rhythmologic tolerance of acetate and bicarbonate hemodialysis using a standard dialyser with high sodium and control of ultrafiltration].

In order to demonstrate a possible superiority of bicarbonate dialysis (HDB) over acetate dialysis (HDA) in conditions of standard dialysis (4 hours on a 1 m2 cuprophan dialyser) but with a bath rich in sodium (143 mEq/l) and control of ultrafiltration, we have compared 2 sequences of 3 runs of HDA and HDB with these conditions in 8 patients as regards their acido-basic and cardiologic parameters (continuous monitoring of ECG by Holter, regular measurement of blood pressure). Acid base balance study in AHD led to the distinction of 2 groups according to wether their plasma bicarbonate increased or decreased during the run. Rythmological tolerance was the same in BHD and AHD, wether all patients or both groups were considered. Heart rate was however slightly but significantly higher during AHD than during BHD, in the patients whose plasma bicarbonate decreased. In conclusion, the benefit of HDB is not remarkable when HDA is performed not only in standard conditions but also with a bath rich in sodium and with control of ultrafiltration.

Acetates↗
PubMed1983

The effects of diffusion and ultrafiltration on cardiac output and organ blood flows.

The effects of diffusion and ultrafiltration on cardiac output (CO) and organ blood flow (BF) in the uraemic dog were studied by a modified microsphere technique. In the diffusion phase of sequential therapy, a decrease in mean arterial pressure (MAP) and total peripheral resistance (TPR) was noted despite no change in circulatory plasma volume (CPV) and CO. In the ultrafiltration (UF) phase, MAP recovered with an increase in TPR despite the decrease in CPV and CO. Muscle vascular resistance increased in UF phase but not in the diffusion phase. The results suggest that the decrease in CPV through UF resulted in CO decrease, but that the compensation mechanism for the decrease is impaired by diffusion.

Animals↗
PubMed1983

[Electrolyte and osmolar changes during extracorporeal ultrafiltration of hepatic cirrhosis ascites].

Ultrafiltration of ascitic fluid with intraperitoneally reinfusion of concentrate was performed on 4 patients with hepatic cirrhosis and ascites. Ascites was removed, ultrafiltered using a parallel plate dialyzer and returned to the peritoneal space via a single catheter. A mean of 4693 ml (range 2000ml-8000ml) of protein free ascitic fluid was removed over the 2-3 hour period of ultrafiltration without evidence of worsening hypovolemia or deterioration of renal function.

Aged↗
PubMed1981

[Clinical use of sequential ultrafiltration with chronic hemodialysis patients].

Twenty one sequential ultrafiltration dialysis were performed to 14 patients with chronic hemodialysis, with a duration of the dialysis treatment from 2 months to 5 years. Dry ultrafiltration--2.1-5.2 litres filtrate was obtained within 90 minutes. The sequential dialysis has numerous advantages over the usual hemodialysis. Apart from the good tolerance of the patients with overweight, some other indications for its performance was stressed upon in the paper, namely: cardiac asthma, arterial hypertension difficult to correct by hemodialysis and drugs, osteodystrophia, itching during dialysis and after it, vomiting and headache during dialysis and in-between dialysis periods, pains in the legs. The patients tolerated the procedure without any complaints.

Acid-Base Equilibrium↗
PubMed1980

[Kinetics of ultrafiltration in peritoneal dialysis with long dialysate dwell: an "in situ" study (author's transl)].

In order to measure in situ the kinetics of peritoneal ultrafiltration in peritoneal dialysis (PD) with long dialysate dwell, a colorimetric method using autologous hemoglobin as a marker added to the dialysis fluid was evaluated in 10 patients on PD for periods ranging from 2 weeks to 20 months. Four different dialysate formulae were successively tested in the same patient. The results expressed as normalised ultrafiltration coefficient (UFK, ml/min/1.73 m2 s.a.) showed a wide scatter among the patients. However, the dilution curves successively obtained with dialysis fluids of varying osmolar concentration in the same patient were very consistent with each other, indicating that UFK was a characteristic of the individual peritoneal membrane. The data presented suggest that UFK should be measured in each patient at initiation of PD in order to prescribe the dialysate formulae and the diffusion times fitting best his individual needs. On the other hand, repetitive measurements of UFK in the same subject would allow a useful analysis of the hydraulic permeability of the peritoneum by detecting any significant change in this parameter during long term PD.

Adult↗