Determination of High and Low Molecular Weight Molecules of Icodextrin in Plasma and Dialysate, Using Gel Filtration Chromatography, in Peritoneal Dialysis Patients

2005 ◽  
Vol 25 (2) ◽  
pp. 181-191 ◽  
Author(s):  
Elvia García–López ◽  
Björn Anderstam ◽  
Olof Heimbürger ◽  
Gianpaolo Amici ◽  
Andrzej Werynski ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Peritoneal Dialysis ◽  
Enzymatic Hydrolysis ◽  
Amylase Activity ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Dialysis Fluid ◽  
Total Carbohydrate ◽  
Accurate Analysis ◽  
Peritoneal Dialysis Fluid

Objective The aim of this study was to apply high performance liquid chromatography (HPLC) with modern gel filtration media to determine high molecular weight (HMW) icodextrin fractions and low molecular weight (LMW) icodextrin metabolites in dialysate and plasma in peritoneal dialysis (PD) patients on treatment with icodextrin, and to explore the potential relationships between these compounds, α-amylase activity, and glomerular filtration rate. Design Retrospective study of dialysate and plasma samples from PD patients. Setting Samples were collected at one PD center. Patients Blood and dialysate samples were obtained from PD patients who were subdivided into three groups: patients using only glucose-based peritoneal dialysis fluid (GPDF; GLU group, n = 23), patients studied after the first long dwell with icodextrin-based peritoneal dialysis fluid (IPDF; 1st ICO group, n = 24), and patients who were regular users of IPDF for the long dwells (ICO group, n = 9). Methods LMW icodextrin metabolites [ i.e., maltose (G2), maltotriose (G3), maltotetraose (G4), maltopentaose (G5), maltohexaose (G6), and maltoheptaose (G7)] and HMW fractions were determined in plasma and dialysate using two different gel filtration HPLC methods. Enzymatic hydrolysis with amyloglucosidase to glucose yielded the total carbohydrate content and this was used to validate the HPLC results. α-Amylase activity was determined using a routine method. Results The results obtained by gel filtration HPLC yielded values of LMW metabolites and HMW fractions in plasma and dialysate in agreement with results obtained with enzymatic hydrolysis. HMW fractions were not detectable in plasma. Absorption of icodextrin from the peritoneal cavity during the long dwell (10 – 16 hours) was, on average, 39% of the amount instilled. During the long dwell, there was a relative decrease in the dialysate concentration of the largest HMW fractions (>21.4 kDa). Plasma concentration of the LMW icodextrin metabolites G2–G7 was highest in the ICO group (2.65 ± 0.54 mg/mL) but also higher in the 1st ICO group (1.97 ± 0.57 mg/mL) compared with the GLU group (0.52 ± 0.23 mg/mL). Plasma α-amylase activity was significantly lower in the 1st ICO group and in the ICO group compared with the GLU group. Conclusions Accurate analysis of HMW icodextrin fractions in dialysate and LMW icodextrin metabolites in plasma and dialysate in PD patients can be achieved by gel filtration HPLC with two different columns. This method can be used to study the complex pattern of changes in icodextrin and its metabolites in plasma and dialysate. The finding that HMW icodextrin fractions were not detected in plasma was unexpected, and differs from results of previous studies by other researchers.

Icodextrin Metabolism and Alpha-Amylase Activity in Nonuremic Rats Undergoing Chronic Peritoneal Dialysis

2007 ◽  
Vol 27 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Elvia García–López ◽  
Krzysztof Pawlaczyk ◽  
Björn Anderstam ◽  
A. Rashid Qureshi ◽  
Malgorzata Kuzlan–Pawlaczyk ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Peritoneal Cavity ◽  
Wistar Rats ◽  
Amylase Activity ◽  
Dialysis Fluid ◽  
Dialysis Patients ◽  
Peritoneal Dialysis Fluid ◽  
Male Wistar Rats ◽  
Osmotic Agent ◽  
Dialysis Solutions

Objective To study the metabolism of icodextrin and α–amylase activity following daily exposure to dialysis solutions containing either glucose or icodextrin as osmotic agent in rats. Methods Male Wistar rats with implanted peritoneal catheters were infused twice daily for 3 weeks with 20 mL 7.5% icodextrin-based peritoneal dialysis fluid (IPDF; ICO group, n = 12) or 3.86% glucose-based peritoneal dialysis fluid (GLU group, n = 11). A 4-hour dwell study using 30 mL IPDF was performed on day 10 (D1) and day 21 (D2) in both the ICO and the GLU groups. Radiolabeled serum albumin (RISA) was used as a macromolecular volume marker. Dialysate samples were collected at 3, 15, 30, 60, 90, 120, and 240 minutes. Blood samples were drawn before the start and at the end of the dwell. Results During all dwell studies, the dialysate concentrations of total icodextrin decreased due to decrease in high molecular weight (MW) fractions, whereas there was a marked increase in icodextrin low MW metabolites. α–Amylase activity increased in dialysate and decreased in plasma. About 60% of the total icodextrin was absorbed from the peritoneal cavity during the 4-hour dwells. Low MW icodextrin metabolites were present in the dialysate already at 3 minutes, and maltose (G2), maltotriose (G3), maltotetraose (G4), and maltopentaose (G5) increased progressively, reaching maximum concentrations at 60 minutes. Maltohexaose (G6) and maltoheptaose (G7) were also detected already at 3 minutes but did not change significantly during the dwells. During the two 4-hour dwell studies (D1 and D2), the concentrations of total icodextrin and icodextrin metabolites and α–amylase activity in dialysate did not differ between the ICO and GLU groups, during either D1 or D2. No icodextrin metabolites were detected in plasma at the end of the dwells. α–Amylase activity in the dialysate increased six- to eightfold whereas plasma α–amylase activity decreased by 21% – 26% during the two 4-hour dwells in both the ICO and the GLU groups; there were no significant differences between the ICO and the GLU groups during either D1 or D2. α–Amylase activity in the dialysate correlated strongly with the disappearance rate of icodextrin from the peritoneal cavity during the 4-hour dwells, and with the concentrations of G2, G3, G6, and G7 in dialysate. Conclusions The decline in the dialysate concentrations of high MW fractions and the increase in low MW metabolites of icodextrin suggest intraperitoneal α–amylase mediated the metabolism of icodextrin and the transport of predominantly the smaller icodextrin metabolites from dialysate. However, no icodextrin could be detected in plasma, suggesting that it was metabolized and excreted by the kidney in these nonuremic rats. In contrast to uremic peritoneal dialysis patients, chronic exposure to IPDF did not seem to further affect α–amylase activity or icodextrin metabolism. The much higher α–amylase activity in plasma and dialysate in rats than in humans explains the much more rapid metabolism of icodextrin in rats compared with peritoneal dialysis patients.

Determination of α-Amylase Activity in Serum and Dialysate from Patients Using Icodextrin-Based Peritoneal Dialysis Fluid

2003 ◽  
Vol 23 (2) ◽  
pp. 146-150 ◽  
Author(s):  
Björn Anderstam ◽  
Elvia García–López ◽  
Olof Heimbürger ◽  
Bengt Lindholm
Keyword(s):  
Peritoneal Dialysis ◽  
Amylase Activity ◽  
Relative Importance ◽  
Routine Method ◽  
Dialysis Fluid ◽  
Peritoneal Dialysis Fluid ◽  
Test Instrumentation ◽  
Healthy Persons ◽  
Low Serum

Objective Low serum activity of α-amylase has been reported in peritoneal dialysis (PD) patients following treatment with icodextrin-based peritoneal dialysis fluid (IPDF). However, these results have been questioned because icodextrin interferes with the polysaccharide reagent included in the assay as a substrate for α-amylase in the sample. Design We adapted a routine method using p-nitrophenol maltoheptaoside as substrate for the analysis of total α-amylase in serum and dialysate from 27 patients using IPDF. Serum from 12 healthy volunteers and serum and dialysate from 19 PD patients using glucose-based peritoneal dialysis fluid (GPDF) were used as controls. For the PD patients, time on dialysis ranged from 1 to 24 months (mean 5.7 months) and time of exposure to IPDF ranged from 1 to 52 weeks. Results To test for interference and recovery, and thus to validate the α-amylase assay, samples were spiked with IPDF and synthetic α-amylase. This revealed that addition of up to 75% IPDF did not interfere with the assay. Furthermore, α-amylase was fully recovered when spiked in serum from patients treated with IPDF. We show that total α-amylase activity is considerably lower in the serum of IPDF patients (20.3 ± 16.5 U/L, p < 0.001) than GPDF patients (85.5 ± 51.7 U/L) and healthy persons (55.1± 13.6 U/L). Conclusions We have shown that the IL method (IL Test; Instrumentation Laboratory, Lexington, MA, USA) measures α-amylase activity in samples containing icodextrin metabolites. The clinical significance of reduced plasma α-amylase activity, as well as the relative importance of pancreatic versus salivary and tissue-bound α-amylase, in PD patients using IPDF is not known.

In Vivo Studies on the Inhibition of Coagulation by Fractionated Heparin and by a Heparin Analogue I. Effects of Heparin Fractions

1981 ◽  
Vol 46 (03) ◽  
pp. 612-616 ◽  
Author(s):  
U Schmitz-Huebner ◽  
L Balleisen ◽  
F Asbeck ◽  
J van de Loo
Keyword(s):  
Molecular Weight ◽  
Day Treatment ◽  
Gel Filtration ◽  
Weight Fraction ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Platelet Factor ◽  
Heparin Fractions

SummaryHigh and low molecular weight heparin fractions obtained by gel filtration chromatography of sodium mucosal heparin were injected subcutaneously into six healthy volunteers and compared with the unfractionated substance in a cross-over trial. Equal doses of 5,000 U were administered twice daily over a period of three days and heparin activity was repeatedly controlled before and 2, 4, 8 hrs after injection by means of the APTT, the anti-Xa clotting test and a chromogenic substrate assay. In addition, the in vivo effect of subcutaneously administered fractionated heparin on platelet function was examined on three of the volunteers. The results show that s.c. injections of the low molecular weight fraction induced markedly higher anti-Xa activity than injections of the other preparations. At the same time, APTT results did not significantly differ. Unfractionated heparin and the high molecular weight fraction enhanced ADP-induced platelet aggregation and collagen-mediated MDA production, while the low molecular weight fraction hardly affected these assays, but potently inhibited thrombin-induced MDA production. All heparin preparations stimulated the release of platelet Factor 4 in plasma. During the three-day treatment periods, no side-effects and no significant changes in the response to heparin injections were detected.

Preparation of low-molecular-weight chitosan by enzymatic hydro-lysis for use in peliculture

2021 ◽  
pp. 31-33
Author(s):  
Элана Игоревна Ковалева ◽  
Марина Алексеевна Фролова ◽  
Алексей Иванович Албулов ◽  
Валерий Петрович Варламов ◽  
Анатолий Константинович Елисеев
Keyword(s):  
Molecular Weight ◽  
Enzymatic Hydrolysis ◽  
Environmental Factors ◽  
Low Molecular Weight ◽  
Technological Parameters ◽  
Low Molecular Weight Chitosan

Хитозан и его производные обладают множеством свойств, которые позволяют применять его в пчеловодстве. Он повышает устойчивость организма пчел к неблагоприятным факторам внешней среды и к возбудителям различных заболеваний. В результате проведенных исследований разработаны технологические параметры получения низкомолекулярного хитозана методом ферментативного гидролиза. Chitosan and its derivatives have many properties that allow them to be used in beekeeping. It increases the resistance of the bee organism to adverse environmental factors and to pathogens of various diseases. As a result of the conducted research, the technological parameters for the production of low-molecular-weight chitosan by enzymatic hydrolysis were developed.

HEMODIALYSIS OF THE RAT

1966 ◽  
Vol 44 (5) ◽  
pp. 849-859 ◽  
Author(s):  
Sumner M. Robinson ◽  
David A. Hurwitz ◽  
Robert Louis-Ferdinand ◽  
William F. Blatt
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Low Molecular Weight

A technique is described for hemodialysis of either anesthetized or non-restrained rats. In the apparatus the dialysis plates of an autoanalyzer system are used with only minor modification. The efficiency of this method has been evaluated with regard to the clearance of saccharides, both in vitro and in vivo, as well as the extraction of nitrogenous low molecular weight moieties from circulating blood. Approximately 50% of the dialyzable material was obtained in a 1-hour dialysis. Further fractionation of the dialyzate was accomplished by gel filtration (Sephadex G-25).

scholarly journals Do We Have a Biocompatible Peritoneal Dialysis Fluid?

2012 ◽  
Vol 02 (03) ◽  
pp. 29-34
Author(s):  
Shadi Hassan ◽  
Batya Kristal ◽  
Khalid Khazim ◽  
Fadi Hassan ◽  
Dunia Hassan ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Dialysis Fluid ◽  
Peritoneal Dialysis Fluid

scholarly journals Peritoneal dialysis fluid inhibition of phagocyte function: effects of osmolality and glucose concentration.

1993 ◽  
Vol 3 (8) ◽  
pp. 1508-1515
Author(s):  
T Liberek ◽  
N Topley ◽  
A Jörres ◽  
G A Coles ◽  
G M Gahl ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Lactate Dehydrogenase ◽  
Glucose Concentration ◽  
Lactate Concentration ◽  
Mononuclear Leukocytes ◽  
Dependent Manner ◽  
Dialysis Fluid ◽  
Glucose Content ◽  
Peritoneal Dialysis Fluid ◽  
Dialysis Fluids

Solutions were formulated to examine, independently, the roles of osmolality and glucose in the reduction of viability and inhibition of phagocyte function by dextrose-containing peritoneal dialysis fluids. The exposure of neutrophils (polymorphonuclear leukocytes) to test fluids containing > or = 2.7% (wt/vol) glucose resulted in significant cytotoxicity as assessed by the release of lactate dehydrogenase above control values (7.12 +/- 2.65%). At the highest concentration of glucose (4.5%), lactate dehydrogenase release was 15.83 +/- 0.49% (P < 0.05). These effects were directly related to the presence of D-glucose in the test fluids. In contrast, phagocytosis and the release of leukotriene B4 from PMN stimulated with serum-treated zymosan were significantly inhibited in an osmolality-, but not glucose-, dependent manner. The inhibition of tumor necrosis factor alpha and interleukin-6 release from mononuclear leukocytes was inhibited by a combination of osmolality and monosaccharide concentration. Under the same conditions, PMN respiratory burst activation remained unaffected irrespective of glucose concentration or fluid osmolality. These data indicate that, in addition to the low pH of peritoneal dialysis fluid and its high lactate concentration, its glucose content (either directly or as a consequence of the resulting hyperosmolality of the fluid) inhibits cell functional parameters. These findings suggest clinically significant inhibition of host defense mechanisms because, in high-glucose dialysis fluids, osmolality does not reach physiologic values, even during extended intraperitoneal dwell periods.

scholarly journals IR-Photometry Method for Measuring Glucose Concentration in Peritoneal Dialysis Fluid

2021 ◽  
Vol 24 (4) ◽  
pp. 68-78
Author(s):  
N. M. Zhilo ◽  
M. O. Mikhailov ◽  
E. L. Litinskaia ◽  
K. V. Pozhar
Keyword(s):  
Peritoneal Dialysis ◽  
Optical System ◽  
Glucose Concentration ◽  
Experimental Studies ◽  
The Body ◽  
Artificial Kidney ◽  
Dialysis Fluid ◽  
Glucose Content ◽  
Peritoneal Dialysis Fluid ◽  
Dialysate Solution

Introduction. The transition of glucose into the blood during automated peritoneal dialysis with regeneration of the dialysis fluid leads to a decreased removal of excess fluid from the body and corresponding violations of the water-salt balance.Aim. To consider a system for automatically maintaining the concentration of glucose in the dialysate solution, which provides effective ultrafiltration, as well as to propose a non-contact photometric feedback sensor.Materials and methods. The sensor is an optical system of an IR laser diode with a power of 30 mW and a wavelength of 1600 nm, a photodiode and a quartz tube, through which the test solution circulates. The sensor measures the attenuation of the radiation passing through the solution in a pulsed mode and calculates the glucose concentration. The selected combination of digital filters provides compensation for the noise of the optical system. Experimental studies of the efficiency of the sensor were carried out on peritoneal dialysis solutions with various concentrations of urea, creatinine, uric acid and glucose. At the beginning of the experiments, the sensor was calibrated in a pure solution.Results. It was shown that the developed sensor makes it possible to measure the concentration of glucose in a solution for peritoneal dialysis in the range of 42…220 mmol / l with a relative error of about 15%. The time of one measurement is about 1 minute, which makes it possible to obtain up-to-date information on the current concentration of the solution.Conclusion. This combination of characteristics will allow the sensor to be used in artificial kidney wearable devices for assessing the glucose content in the solution, calculating the time to change the solution and as a feedback sensor in a system for maintaining the concentration of the osmotic agent.

scholarly journals Role of serum IgA. Hepatobiliary transport of circulating antigen.

1981 ◽  
Vol 153 (4) ◽  
pp. 968-976 ◽  
Author(s):  
M W Russell ◽  
T A Brown ◽  
J Mestecky
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Serum Iga ◽  
Circulating Antigen ◽  
Circulating Antigens ◽  
Iga Antibody ◽  
Immune Spleen Cell

The IgA mediated hepatobiliary excretion of antigen from the circulation was studied using a radiolabeled haptenated protein (dinitrophenyl-human serum albumin) injected intravenously in mice together with monoclonal anti-dinitrophenyl antibodies of different immunoglobulin classes. Antibodies were obtained from ascitic fluids of mice bearing the MOPC315 myeloma (IgA), or immune spleen cell hybridomas (IgG and IgM). IgA antibody brought about the transport of large amounts of antigen from the circulation to the bile during 1-3h. Analysis of bile by gel filtration showed that a large part of the transported antigen remained intact and complexed with IgA. Neither IgA of different specificity nor anti-dinitrophenyl IgM medicated biliary transport of antigen. With anti-dinitrophenyl IgG, only small amounts of low molecular weight fragments of labeled antigen were found in he bile. Preformed immune complex of radiolabeled antigen and IgA antibody were rapidly transported from the circulation to the bile, resulting in threefold-higher levels of radioactivity in bile than in serum. It is proposed that an important function of serum IgA is to mediate the hepatobiliary excretion of corresponding circulating antigens.

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