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Results for “Ultrafiltration”

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At least 1,099 records · Page 61Linked to original sources

PubMed2000

[Experimental study on effect of ligustrazine on peritoneal ultrafiltrative function in rats].

OBJECTIVE: To study the effect of ligustrazine on peritoneal transport in various dosages. METHODS: Forty SD rats received intraperitoneal injection of 25 ml 4.25% glucose dialysis solution (GDS) or GDS plus 40 mg/L ligustrazine (GDS-LL) or GDS plus 160 mg/L ligustrazine (GDS-HL) daily, for 45 days. Then a 4-hour dwell study was performed in each rat to evaluate the peritoneal transportation. RESULTS: The drainage volume at 4 hours was significantly lower in all the dialysis groups as compared to the control group, especially in the GDS-HL group. However, drainage volume was significantly higher in the GDS-LL group as compared to the GDS and GGS-HL groups. There were no significant differences in the peritoneal fluid absorption rate among the 3 dialysis groups. The fluid absorption rate and the direct lymphatic absorption rate were all significantly higher in the 3 dialysis groups as compared to the control group. In the GDS-LL group, the ratio of urea level in dialysis solution and in plasma (D/Purea) was not different in comparing with that in the GDS group, but the ratio of glucose concentration in dialysis solution and that in unused dialysis solution (D/D0), and urea clearance were significantly higher than those in the GDS group and the GDS-HL group. D/Purea increased in the GDS-HL group significantly. CONCLUSION: Low dose of ligustrazine adding to the dialysis solution could reduce the peritoneal damage caused by the hypertonic dialysis solution, increase the ultrafiltration function and dialysis function of peritoneum. However, high dose of ligustrazine does not display any beneficial effect, it increases the permeability of peritoneum.

Animals↗

PubMedDate not supplied

[Trypsin concentration by ultrafiltration].

Criteria for the selection of membranes and optimal conditions for the trypsin concentration by ultrafiltration through acetylcellulose membranes have been developed. The possibility of a repeated concentration of trypsin by means of these membrances has been shown.

Trypsin↗

PubMed2002

Alleviating heat loss associated with modified ultrafiltration.

Modified ultrafiltration (MUF) has been described and utilized for the removal of extracellular water in the immediate postcardiopulmonary bypass (CPB) period. This technique has been associated with improved hematological status and hemodynamic stability post cardiopulmonary bypass. Hypothermia during the MUF period has been described as a complication associated with this technique. Decreased patient temperature may be associated with increased bleeding causing an increase in time to sternal re-approximation, OR time, decreases in cardiac function, peripheral vascular perfusion, and an increase in blood product utilization. These complications may reduce some of the benefits described with the use of MUF. The purpose of this study was to evaluate the use of a heated MUF infusion line to reduce the heat loss associated with this technique in a pediatric population. After obtaining Committee for Protection of Human Subjects exemption, a retrospective review to evaluate the efficiency of the hot MUF infusion line was undertaken. Twenty patients under 10 kg who underwent MUF before the change to a heated infusion line were retrospectively identified and matched to patients undergoing MUF with a heated infusion line with regard to weight, lesion, procedure, surgical staff and technique, and disposable equipment. Groups were evaluated for temperature and hematocrit change during the MUF period, blood loss and transfusion postprotamine in the OR and 24 h, and time to sternal re-approximation postprotamine. Statistical significance was seen between the two groups in temperature (-0.24 +/- 0.72 vs. - 1.58 +/- 0.89 degrees C; p < .0001) with the HotLine group having little change post MUF. Significance was also seen in the last OR temperature recorded (37.0 +/- 1.2 vs. 36.0 +/- 1.0 degrees C; p = .01) with the HotLine group having the higher temperature. There were no significant differences in hematocrit levels at 24 hours, last in the OR, or the change after the MUF period. No significant difference was found in blood transfused postprotamine in the OR, 24-h blood transfused, 24-h chest tube loss, or sternal closure. The study suggests that the use of a heated MUF infusion line safely reduces the heat loss associated with MUF in the immediate post-operative period.

Body Temperature Regulation↗

PubMedDate not supplied

[Effect of several factors on the process of protein solution ultrafiltration].

Ultrafiltration of protein solutions was investigated, using deoxyribonuclease of Actinomyces streptomycini filtered through a membrane based on vinylpyrrolidone-methyl methacrylate copolymers. It was shown that ionization of the protein molecule, level of the applied pressure as well as the protein concentration in the initial solution influenced particle adsorption on the surface and in pores of the molecule and the formation of gel layer reducing the rate of the solution filtration. The following parameters were found to favor the process: pH=7.5 (the value corresponds to the highest stability of the enzyme and the presence of the total negative discharge on the surface of the protein molecule). DNase concentration not more than 2 mg/ml, pressure 2 atm. The retaining capacity of the membrane was 85% and DNAase losses were 20%.

Actinomyces↗

PubMed2002

High-volume, zero balanced ultrafiltration improves pulmonary function in a model of post-pump syndrome.

The systemic inflammatory response syndrome (SIRS), which may develop following cardiopulmonary bypass (CPB), can cause postoperative complications that contribute to the morbidity and mortality associated with open-heart surgery. Inflammatory mediators such as cytokines, are thought to play an important role in SIRS. Zero Balance Ultrafiltration (Z-BUF) is thought to reduce the quantity of inflammatory mediators associated with CPB and may attenuate the adverse effects of bypass. Following ethics committee approval, both an unfiltered experimental group and Z-BUF treatment group consisting of Yorkshire pigs (41 +/- 19 kg) were anesthetized, ventilated, instrumented, cannulated and placed on CPB for 60 minutes. Following CPB, an infusion of low-dose endotoxin (1 microg/kg) was administered I.V. and the animals were monitored for 3.5 hours. The Z-BUF treatment group (n = 5) received high-volume Z-BUF (122 ml/kg +/- 41) and the unfiltered experimental group (n = 5) did not. Hemodynamics, blood gases, and pulmonary functions were measured before, during, and after CPB. Following euthanasia, the middle lobe of the lung was prepared for histological analysis. Necropsy of the lung sample was weighed before and after dehydration to evaluate lung water content. During the experimental time course, plasma samples were evaluated for Interleukin-8 (IL-8) concentrations. Arterial PO2's (mmHg) in the unfiltered experimental group showed a significant reduction at 3.5 hours post CPB when compared to baseline while the Z-BUF treatment group PaO2 did not significantly change. There was a significant difference in the PaO2 between the unfiltered experimental and Z-BUF group at the final 3.5 hour time point (78 +/- 32 vs. 188 +/- 92 mmHg respectively). Pulmonary compliance (ml/cmH2O) was significantly reduced in both the unfiltered experimental and Z-BUF treatment groups with the unfiltered experimental group being the most significant. Lung wet/dry ratios were established and results found the unfiltered experimental group ratio significantly greater than that of the Z-BUF treatment group. Morphometric analysis of histologic lung sections confirmed pulmonary injury in the unfiltered experimental group and protection in the Z-BUF treatment group. This study suggests that Z-BUF provides higher arterial PO2's and lung compliances while reducing pulmonary edema and lung injury in a porcine model of PPS.

Animals↗

PubMed2000

[Determination of sialic acids in serum of lung cancer with ultrafiltration-capillary electrophoresis].

A method for the determination of sialic acids in serum with ultrafiltration-capillary electrophoresis is described and the operation was optimized. Sialic acids were directly separated and analyzed with UV detection at 195 nm and without pre-or post-column derivatization. The recovery of N-acetylneuraminic acid (NANA) was 92.6%, the concentration and mass detection limit of NANA were 9.6 mumol/L and 39 fmol respectively. This method was used for the determination of NANA level in the serum of 11 lung cancer patients and 30 normal adults. The results showed that the average concentration of NANA in the serum of patients was much higher than that of normal adults with P < 0.001. The results were also compared with those obtained by the traditional colorimetric method, with good linear relationship of r = 0.983 at n = 10. It is concluded that the method described in this paper is simple and sensitive, and is suitable for basic research and clinical applications to malignant tumors.

Adult↗

PubMed1999

[Treatment of refractory cardiac insufficiency by peritoneal ultrafiltration. Literature review].

The management of heart failure that has become refractory to conventional drug treatment is an increasingly frequent problem for clinicians. Peritoneal dialysis, by ultrafiltration, is an effective method to treat refractory oedema, thereby improving the functional symptoms of these patients. The objective of this article is to review the data, of the literature and to define the results and indications of this treatment, which still remains and exceptional modality.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1992

In vitro plasma perfusion through adsorbents and plasma ultrafiltration to remove endotoxin and cytokines.

In vitro plasma perfusion experiments were performed using small columns containing either resin or charcoal adsorbents to assess the removal of cytokines and endotoxin. 125I-labelled tumor necrosis factor-alpha (TNF-alpha; 500 pg/ml) and interleukin-6 (IL-6; 10 ng/ml) were added individually to human plasma. Over 4 hr of perfusion, Amberlite XAD-7 resin removed 32.5% +/- 3.3% (n = 5) of the initial amount of TNF-alpha and 71.4% +/- 3.8% (n = 5) of the initial amount of IL-6. DHP-1 polyhema-coated activated charcoal removed 17.2% +/- 6.2% (n = 5) of TNF-alpha and 48.5% +/- 7.4% (n = 5) of IL-6. Preliminary experiments were performed with lipopolysaccharide (LPS; 100 ng/ml) and interleukin-1 alpha (IL-1 alpha; 500 pg/ml), which showed that, over 4 hr, Amberlite XAD-7 removed 10.3% of the initial LPS and 29.1% of IL-1 alpha, whereas DHP-1 charcoal removed 23.2% of the initial LPS and 65.3% of IL-1 alpha. In vitro plasma ultrafiltration with either polysulfone or polyacrylonitrile membranes, as used clinically in haemodialysis, was performed with recirculation of plasma containing LPS or TNF-alpha. Neither of the substances was filtered to a significant degree. In conclusion, direct removal of these inflammatory mediators from the circulation of patients with multiorgan failure due to fulminant hepatic failure or sepsis would be possible by perfusion of plasma through adsorbents but not by haemodialysis.

Adsorption↗

PubMedDate not supplied

Peritoneal ultrafiltration and serum icodextrin concentration during dialysis with 7.5% icodextrin solution in Japanese patients.

OBJECTIVES: To assess the efficacy and safety of icodextrin in Japanese patients and to investigate the relationship between net ultrafiltration (UF) during the long dwell and plasma oligosaccharides. DESIGN: Open-labeled clinical trial involving patients on continuous ambulatory peritoneal dialysis (CAPD) receiving icodextrin during the 12-hour long dwell for 6 weeks, preceded by and followed by a 2-week baseline period and a follow-up period during which 1.36% glucose was used for the 8-hour long dwell. SETTING: A prospective, randomized multicenter study done in tertiary medical centers. PATIENTS: 18 stable patients on CAPD for 3 months or longer. MAIN OUTCOMES MEASURES: Net UF (in milliliters), UF rate (in milliliters per hour), plasma oligosaccharides, serum osmolarity (in milliosmoles per liter), peritoneal absorption of icodextrin, and peritoneal clearances of icodextrin, creatinine, and urea were assessed. Adverse events, laboratory findings, and vital signs were also monitored. RESULTS: Long-dwell net UF (544.4 +/- 96.7 mL at day 3, p < 0.001; 309.4 +/- 60.7 mL at week 4, p < 0.001; and 391.7 +/- 61.1 mL at week 6, p < 0.001) and UF rate (48.2 +/- 38.8 mL/ hour at day 3, p < 0.001; 26.9 +/- 22.1 mL/hr at week 4, p < 0.002; and 35.3 +/- 22.9 mL/hr at week 6, p = 0.0002) were significantly greater during the icodextrin period than at baseline (-25.9 +/- 46.0 mL and -2.2 +/- 22.1 mL/hr, respectively). Plasma oligosaccharides reached steady state within 2 weeks, remained stable during the treatment period, and returned to baseline level 2 weeks after discontinuation of icodextrin. Serum osmolarity increased during the use of icodextrin by approximately 5 mOsm/L. No statistically significant relationship was found between plasma oligosaccharides and net UF. Peritoneal absorption of icodextrin (36.3% +/- 5.1% at day 3, 42.2% +/- 5.9% at week 4, and 38.0% +/- 6.3% at week 6) and peritoneal clearance of icodextrin (10.1 mL/minute at day 3, 10.1 mL/min at week 4, and 10.3 mL/min at week 6) showed no major change over time. Serum sodium and serum chloride both decreased by 5 mEq/L with icodextrin but remained within the normal range during the treatment period and returned to baseline levels immediately after discontinuation. No serious adverse events were observed during the study. CONCLUSION: The results of this study do not support the hypothesis that an increased blood oligosaccharide level and the concomitant elevation in serum osmolarity have a negative impact on peritoneal UF. Therefore, the increase in plasma oligosaccharides appears to be too small to be of clinical significance.

Dialysis Solutions↗

PubMed1992

Symptomatic accidental introduction of disinfectant electrolytic chloroxidizer solution into the peritoneal cavity of CAPD patients. Incidence and long-term effects on ultrafiltration.

In recent years the Y-set with disinfectant [Buoncristiani et al. 1983] has been used in several continuous ambulatory peritoneal dialysis (CAPD) centers. This system has considerably improved the short- and long-term results of CAPD [Maiorca et al. 1983, Scalamogna et al. 1990]. Accidental introduction of disinfectant during the exchange is a risk associated with this system, but at the present time we have little data pertaining to incidence complication and its possible effects on peritoneal function. The aim of the present study was to assess the incidence of acute symptomatic accidental introduction of disinfectant in CAPD patients on the Y system and to establish whether this complication is followed by any long-term changes in peritoneal ultrafiltration.

Adult↗

PubMed1992

An Na, K ATPase inhibitor from ultrafiltrate obtained by hemodialysis of patients with uremia.

Ultrafiltrate obtained by hemodialysis of patients with uremia who were not taking cardiac glycosides was used as a source of Na, K adenosine triphosphatase inhibitor for purification and further study. Inhibitory activity was measured by a linked-enzyme assay and by effect on rubidium 86 uptake in guinea pig aortic strips. Two approaches were used in purification: dialysis with a 500 dalton membrane followed by gel filtration with Sephadex G-25, and removal of protein by acidification and boiling followed by Sephadex G-10. The first procedure failed to separate the inhibitor from the salt fraction, whereas the second separated the inhibitor from the salt peak but resulted in partial coelution of the inhibitor with endogenous pyruvate, which interferes with the linked-enzyme assay. Pooled, concentrated G-10 elution fractions from the early part of the inhibitor peak, which were free of pyruvate, produced a dose-response relationship by enzymatic assay that was close to parallel with that for ouabain. Like ouabain, these fractions also inhibited 86Rb uptake in guinea pig aorta. Despite these properties, our previous work has demonstrated that the inhibitor, unlike some other ouabain-like or digitalis-like substances obtained from blood or urine, has no apparent role in body fluid homeostasis.

Animals↗

PubMed1992

[Nutritional quality of a protein concentrate of chick-peas (Cicer arietinum) obtained by ultrafiltration].

The nutritive quality of a protein concentrate from chickpea (Cicer arietinum) obtained by ultrafiltration was evaluated. Three biological assays and the apparent protein digestibility (APD) were utilized. In addition, the effect of the supplementation with methionine to protein concentrate was observed. The protein efficiency ratio (PER), net protein ratio (NPR) and nitrogen utilization (NU) were 1.86, 3.11 and 3.11 respectively, compared with the values of casein ANRC of 2.50 4.02 y 4.01. Only the PER of the protein concentrate from chick-pea (Cicer arietinum) was increased significantly (< 0.05) higher with respect to raw chick-pea (Cicer arietinum), but lower with respect to casein ANRC.

Animals↗

PubMed1992

Intraperitoneal pressure, peritoneal permeability and volume of ultrafiltration in CAPD.

Peritoneal permeability (PP), hydrostatic intraperitoneal pressure (IPP) and the overall volume of ultrafiltration (UF) were measured in 23 patients treated by CAPD under stable conditions. PP, IPP and UF were measured during the same exchange with a 2-liter bag with 3.86% glucose, dwell time of 2 hours. PP was evaluated with 3 indices: glucose peritoneal desaturation at 2 hours, urea peritoneal saturation at 2 hours, and crossing time of glucose and urea peritoneal equilibration curves. IPP was evaluated at inspiration (IPPinsp) and at expiration (IPPexp)-giving IPPmean-by measuring the height of the dialysis fluid in the PD line under atmospheric pressure, with point zero located on the axillary line of the subject in strict supine position. Net UF volume was inversely correlated with IPPmean. The net UF volume was strongly affected by IPP since a 1 cmH2O increase in IPPmean caused a decrease of 74 ml in global UF in 2 hours, probably by modification of the lymphatic reabsorption and perhaps of the transcapillary UF.

Adult↗

PubMed1991

Effects of periodic backflushing on ultrafiltration performance.

Periodic backflushing was introduced to a membrane separation process to improve the performance. Hemoglobin (M.W. = 62,500) and dextran (M.W. = 10,000) were used as model compounds. Filtration performance of an ultrafiltration membrane system (Amicon hollow fiber membrane, H1P30-43, molecular weight cutoff = 30,000) was measured in terms of apparent permeability and retention coefficient of dextran to determine the effects of backflushing frequency and duration of one cycle. An optimum frequency around 0.2 min-1 existed to give a maximum permeability while the retention of dextran decreased with increasing frequencies. The improvement in permeability by periodic backflush was more than doubled. The retention of dextran decreased as backflushing duration was increased in one cycle. With the duration of 33.75 s, the retention of dextran was less than 50% and dextran output was 1.14 g/h, which was 1.3 times the value without backflushing. Also, periodic backflush made possible the long-term filtration of yeast cells for more than 20 h.

Dextrans↗

PubMed1992

Efficient purification of PCR products using ultrafiltration.

The use of disposable ultrafiltration devices for the purification of PCR-amplified DNA products from the other components of the reaction mixture is outlined. The advantages of using a 100,000 molecular weight cutoff membrane are discussed. The integrity of the membrane-purified DNA is checked by its successful use in sequencing, ligation and cloning procedures.

DNA↗

PubMedDate not supplied

[Experimental evaluation of the allergen activity of a peptide preparation produced from an enzymatic hydrolysate of milk proteins using ultrafiltration].

Noninbred guinea-pig experiments were performed to investigate specific potential allergenicity of cow milk proteins (CMP) consisting of casein (80%) and serum proteins (20%), of low-molecular peptides (LMP 20/80) produced from CMP 20/80 by enzymatic hydrolysis and ultrafiltration; to evaluate nonspecific effect of test diet CMP 20/80 and LMP 20/80 on anaphylactic response of the animals to ovalbumin and histamine LD50. LMP 20/80 versus CMP 20/80 had a hypoallergenic effect. Potential mechanisms of low anaphylactic sensitivity induced by LMP 20/80 are discussed.

Allergens↗

PubMed2003

Modified ultrafiltration postextracorporeal membrane oxygenation.

Modified ultrafiltration (MUF) has been widely used for the removal of extracellular water in the immediate postcardiopulmonary bypass (CPB) period. The reported benefits of this technique are improved hematological status and hemodynamic stability post-CPB, as well as a decrease in blood utilization during the operation. MUF has also been associated with improved pulmonary status along with enhanced myocardial performance. With these benefits in mind, we have explored the possible advantages of using MUF following extracorporeal membrane oxygenation (ECMO). The theoretical advantages of using MUF post-ECMO are the reduction of blood use prior to removal from ECMO for optimization of hemoglobin levels, improved pulmonary compliance decreasing the duration of ventilatory support, improved myocardial function, as well as the other reported benefits described with MUF post-CPB. This report communicates the technique used to perform MUF post-ECMO, as well as a simple MUF circuit design for use in the intensive care unit setting.

Cardiopulmonary Bypass↗

PubMed2003

Dialysate interleukin-15 concentration and ultrafiltration capacity in patients undergoing peritoneal dialysis.

Our aim in the present study was to simultaneously determine, in peritoneal dialysis (PD) patients, interleukin-15 (IL-15) concentrations in serum and dialysate, peritoneal transport parameters, and ultrafiltration (UF). The study was performed in 42 patients who had been treated with PD for 24.5 +/- 20.1 months. Concentration of IL-15 was measured (ELISA: IBL, Hamburg, Germany) during a peritoneal equilibration test. Of 42 patients, 69% had serum IL-15 concentrations above normal values (< 13.0 pg.mL). The mean dialysate-to-plasma ratio (D/P) for IL-15 exceeded 1. We observed a negative relationship between dialysate IL-15 and effluent volume. Patients with UF < or = 200 mL or < 100 mL had higher dialysate IL-15 concentration, higher D/P for IL-15, higher mass transfer area coefficient (KBD) for creatinine, and higher dialysate creatinine concentration than patients with more UF. The KBD for creatinine correlated negatively with dialysate effluent volume. We conclude that, in PD patients, elevated serum and dialysate IL-15 concentrations confirm the existence of systemic and local inflammation; the source of IL-15 in dialysate is not only serum, but also local generation in the peritoneum; and dialysate IL-15 concentration may be a marker of UF capacity.

Dialysis Solutions↗