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Raymond Vanholder - One of the best experts on this subject based on the ideXlab platform.
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impact of hemoDialysis duration on the removal of uremic retention solutes
Kidney International, 2008Co-Authors: Sunny Eloot, Pascal Verdonck, W Van Biesen, A Dhondt, H Van De Wynkele, Griet Glorieux, Raymond VanholderAbstract:Several studies have stressed the importance of Dialysis time in the removal of uremic retention solutes. To further investigate this, nine stable chronic hemoDialysis patients were dialyzed for 4, 6, or 8 h processing the same total blood and dialysate volume by the Genius system and high-flux FX80 dialyzers. Inlet blood and outlet dialysate were analyzed for urea, creatinine, phosphorus, and β2-microglobulin at various times. Total solute removal, dialyzer extraction ratios, and total cleared volumes were significantly larger during prolonged Dialysis for urea, creatinine, phosphorus, and β2-microglobulin. Reduction ratios increased progressively, except for phosphate and β2-microglobulin, where the ratios remained constant after 2 h. In contrast, no significant difference was found for the reduction ratios of all solutes and Kt / V urea between the three different sessions. With longer dialyses, solutes are efficiently removed from the deeper compartments of the patient's body. Our study shows that care must be taken when using Kt / V urea or reduction ratios as the only parameters to quantify Dialysis adequacy.
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Randomised Long-Term Comparison of Tinzaparin and Dalteparin in HaemoDialysis
Clinical Drug Investigation, 2003Co-Authors: Rolinda J. R. Beijering, P Sprogel, Hugo Cate, Paul Stevens, Raymond Vanholder, Wim T. Dorp, Rudolf W. Olden, Björn Wickström, Jan W. CateAbstract:Objective and design Tinzaparin and dalteparin are low molecular weight heparins (LMWHs) with different pharmacokinetic and pharmacodynamic profiles that may lead to differences in efficacy and safety. In a long-term, multicentre, prospective, randomised trial we compared the efficacy and safety profiles of tinzaparin and dalteparin (starting doses were adjusted to comparable anti-IIa activity). The sample size was calculated to show a relative difference of 50% in unsatisfactory dialyses with a power of 80% (to prove superiority). Patients 159 patients undergoing chronic intermittent haemoDialysis were included in the study. Main outcome measures Efficacy was assessed by scoring the dialyser (from 1 = good, clear dialyser to 4 = total clotting of the dialyser requiring a change of the extracorporeal circuit) and bubble catcher (from 1 = no clots to 4 = severe clotting) after each Dialysis. Levels of thrombin antithrombin complexes (TAT) were also determined. Safety was assessed by noting all minor and major bleeding. Results The mean anticoagulant dose for tinzaparin during the maintenance phase was about 10% lower than that of dalteparin: 5024 ± 2321 (range 700–12000) anti-Xa IU and 5546 ± 2395 (1875–12913) anti-Xa IU, respectively. No difference was found between treatments in clotting for either the dialyser or the bubble catcher (p = 0.59). TAT levels showed no difference between tinzaparin and dalteparin. The number of minor bleeds did not differ between treatments: 1.5% (40/2629 dialyses) for tinzaparin and 1.4% (41/2863 dialyses) for dalteparin, and one major bleed occurred in each treatment arm. Conclusions Dose calculation of tinzaparin and dalteparin according to anti-IIa activity resulted in equivalent efficacy and safety, although this was achieved with a 10% lower dose of tinzaparin measured in anti-Xa IU. Both LMWHs can be safely administered over a wide dosage range in patients undergoing long-term intermittent haemoDialysis.
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renal replacement therapies in the aftermath of the catastrophic marmara earthquake
Kidney International, 2002Co-Authors: Mehmet Sukru Sever, Raymond Vanholder, Ekrem Erek, Birsen Yurugen, Gulcin Kantarci, Mahmut Yavuz, Hulya Ergin, Semra Bozfakioglu, Serran Dalmak, Yasar M TulbekAbstract:Renal replacement therapies in the aftermath of the catastrophic Marmara earthquake. Background Renal replacement therapy is of vital importance in the treatment of crush syndrome victims, who are frequently encountered after catastrophic earthquakes. The Marmara earthquake, which struck Northwestern Turkey in August 1999, was characterized by 477 victims who needed Dialysis. Method Within the first week of the disaster, questionnaires containing 63 clinical and laboratory variables were sent to 35 reference hospitals that treated the victims. Information considering the features of dialyses obtained through these questionnaires was submitted to analysis. Results Overall, 639 casualties with renal complications were registered, 477 of whom (mean age 32.3 ± 13.7 years, 269 male) needed Dialysis. Among these, 452 were treated by a single Dialysis modality (437 intermittent hemoDialysis, 11 continuous renal replacement therapy and 4 peritoneal Dialysis), while 25 victims needed more than one type of Dialysis. In total, 5137 hemoDialysis sessions were performed (mean 11.1 ± 8.0 sessions per patient) and mean duration of hemoDialysis support was 13.4 ± 9.0 days; this duration was shorter in the non-survivors (7.0 ± 8.7 vs. 10.0 ± 9.8 days, P = 0.005). Thirty-four victims who underwent continuous renal replacement therapy had higher mortality rates (41.2 vs. 13.7%, P P = 0.015). Conclusion Substantial amounts of Dialysis support may be necessary for treating the victims of mass disasters complicated with crush syndrome. Dialyzed patients are characterized by higher rates of morbidity and mortality.
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Recombinant hirudin: clinical pharmacology and potential applications in nephrology.
BioDrugs : clinical immunotherapeutics biopharmaceuticals and gene therapy, 1999Co-Authors: Raymond Vanholder, Annemieke DhondtAbstract:The last decade has been characterised by the development of several anticoagulation methods as alternatives to the heparins. One of these is the antithrombin hirudin, which is now available on a large scale in the recombinant form. The application of hirudin as an anticoagulant in haemoDialysis has been complicated by the decrease of its clearance in patients with renal failure. The half-life of hirudin is more than 30 times longer in haemoDialysis patients than in healthy subjects. Therefore, at present, its use in the haemoDialysis setting is essentially limited to heparin-induced thrombocytopenia (HIT). Hirudin has been used sporadically and with success in nonrenal failure patients with HIT and at least once on a regular basis in a haemoDialysis patient. A starting dose between 0.08 and 0.15 mg/kg for the first Dialysis, followed by 50% of this quantity during the following dialyses is recommended. Hirudin activity can be monitored by aiming for threshold activated partial thromboplastin time (aPTT) values between 60 and 90 seconds, with urgent dosage adaptations once aPTT rises above 100 to 120 seconds. Hirudin concentrations during Dialysis should be maintained between 400 and 1000 microg/L, with determination by ecarin clotting time or chromogenic assays. At present, the use of hirudin is also limited by the absence of an effective antidote. In studies in humans, no enhanced removal of hirudin was observed during Dialysis with large pore dialysers in contrast to earlier published animal studies.
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pharmacokinetics of recombinant hirudin in hemodialyzed end stage renal failure patients
Thrombosis and Haemostasis, 1997Co-Authors: Raymond Vanholder, A Camez, Nic Veys, A Van Loo, Annemieke Dhondt, S RingoirAbstract:Recently, hirudin was used for the first time as an anticoagulant during hemoDialysis in men. Pharmacokinetic data of this compound in end-stage renal failure are however not available. In this study, the pharmacokinetics of recombinant hirudin (HBW 023) was evaluated in hemoDialysis-treated end-stage renal failure patients. HBW 023 was administered as a bolus at the start of a single Dialysis (0.02 to 0.08 mg/kg) in 20 patients, and plasma hirudin levels were followed during this and the 5 following dialyses, without additional hirudin administration. The initial Dialysis (HD1) was performed with a low flux polysulfone dialyzer, the following dialyses (up to HD6) with a high flux polysulfone dialyzer and regular heparin. Hirudin levels averaged 504.0 +/- 214.0 and 527.7 +/- 217.1 ng/ml in the middle and at the end of HD1, and then gradually decreased to 15.2 +/- 15.2 ng/ml at the end of HD6. Pharmacokinetic data were compared to those obtained in healthy controls (n = 5), receiving the same dose, and reaching the same peak hirudin level. Hirudin half-life was > 30 times longer in hemoDialysis patients (51.8 +/- 15.6 vs. 1.7 +/- 1.5 h, p 60 times higher (34,669 +/- 14,898 vs. 545 +/- 205 ng/ml x h, p < 0.001). Distribution volume was lower in hemoDialysis patients (11.0 +/- 3.1 vs. 14.1 +/- 2.01, p < 0.05). Hirudin disappearance rate was the same during high flux polysulfone Dialysis as during interdialytic periods. Hirudin removal was markedly higher in those patients still maintaining some residual renal function and parameters of hirudin removal were significantly correlated to residual creatinine clearance. It is concluded that hirudin removal from the body is markedly depressed in hemodialyzed end-stage renal failure patients and that even minor residual renal function may increase this removal rate.
Toyohiko Nishizawa - One of the best experts on this subject based on the ideXlab platform.
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Purification of nervous necrosis virus (NNV) particles by anion-exchange chromatography.
Journal of virological methods, 2016Co-Authors: Hyun Jung Gye, Toyohiko NishizawaAbstract:Nervous necrosis virus (NNV) belongs to genus Betanodavirus (family Nodaviridae). It is highly pathogenic to various marine fishes. In the present study, cultured NNV suspension was placed in Dialysis tube at molecular weight cut off (MWCO) of 106 and dialyzed against Dulbecco's phosphate buffered saline (D-PBS), 15mM Tris-HCl (pH 8.0), or deionized water (DIW) for 14days followed by anion-exchange chromatography. Infectivity titers of NNV suspensions were stable during dialyses. However, the antigenicity of NNV suspension was decreased to 2.5% by D-PBS Dialysis, 11.8% by Tris-HCl Dialysis, and 56.2% by DIW Dialysis. Anion-exchange chromatograms revealed a total of four peaks (P300, P400, P600 and P700) for NNV suspension after D-PBS Dialysis. Additional two peaks (P800 and P-OH) were detected in the NNV suspension after Tris-HCl or DIW Dialysis. The substance from the P700 peak had the highest NNV-infectivity. Peak P700 commonly shared by the NNV suspensions after Dialysis against the three different buffers. After Tris-HCl Dialysis, no other protein except NNV coat protein (CP) at Mr 41,000 was detected from P700. However, after D-PBS Dialysis, the P700 peak also contained P600 antigens. Therefore, the P700 peak after Tris-HCl Dialysis represented the peak of highly purified NNV particles.
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Dialysis buffer with different ionic strength affects the antigenicity of cultured nervous necrosis virus (NNV) suspensions
Virus research, 2016Co-Authors: Hyun Jung Gye, Toyohiko NishizawaAbstract:Nervous necrosis virus (NNV) belongs to the genus Betanodavirus (Nodaviridae). It is highly pathogenic to various marine fishes. Here, we investigated the antigenicity changes of cultured NNV suspensions during 14days of dialyses using a Dialysis tube at 1.4×10(4) molecular weight cut off (MWCO) in three different buffers (Dulbecco's phosphate buffered saline (D-PBS), 15mM Tris-HCl (pH 8.0), and deionized water (DIW)). Total NNV antigen titers of cultured NNV suspension varied depending on different Dialysis buffers. For example, total NNV antigen titer during D-PBS Dialysis was increased once but then decreased. During Tris-HCl Dialysis, it was relatively stable. During Dialysis in DIW, total NNV antigen titer was increased gradually. These antigenicity changes in NNV suspension might be due to changes in the aggregation state of NNV particles and/or coat proteins (CPs). ELISA values of NNV suspension changed due to changing aggregates state of NNV antigens. NNV particles in suspension were aggregated at a certain level. These aggregates were progressive after D-PBS Dialysis, but regressive after Tris-HCl Dialysis. The purified NNV particles self-aggregated after Dialysis in D-PBS or in Tris-HCl containing 600mM NaCl, but not after Dialysis in Tris-HCl or DIW. Quantitative analysis is merited to determine NNV antigens in the highly purified NNV particles suspended in buffer at low salt condition.
S Ringoir - One of the best experts on this subject based on the ideXlab platform.
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pharmacokinetics of recombinant hirudin in hemodialyzed end stage renal failure patients
Thrombosis and Haemostasis, 1997Co-Authors: Raymond Vanholder, A Camez, Nic Veys, A Van Loo, Annemieke Dhondt, S RingoirAbstract:Recently, hirudin was used for the first time as an anticoagulant during hemoDialysis in men. Pharmacokinetic data of this compound in end-stage renal failure are however not available. In this study, the pharmacokinetics of recombinant hirudin (HBW 023) was evaluated in hemoDialysis-treated end-stage renal failure patients. HBW 023 was administered as a bolus at the start of a single Dialysis (0.02 to 0.08 mg/kg) in 20 patients, and plasma hirudin levels were followed during this and the 5 following dialyses, without additional hirudin administration. The initial Dialysis (HD1) was performed with a low flux polysulfone dialyzer, the following dialyses (up to HD6) with a high flux polysulfone dialyzer and regular heparin. Hirudin levels averaged 504.0 +/- 214.0 and 527.7 +/- 217.1 ng/ml in the middle and at the end of HD1, and then gradually decreased to 15.2 +/- 15.2 ng/ml at the end of HD6. Pharmacokinetic data were compared to those obtained in healthy controls (n = 5), receiving the same dose, and reaching the same peak hirudin level. Hirudin half-life was > 30 times longer in hemoDialysis patients (51.8 +/- 15.6 vs. 1.7 +/- 1.5 h, p 60 times higher (34,669 +/- 14,898 vs. 545 +/- 205 ng/ml x h, p < 0.001). Distribution volume was lower in hemoDialysis patients (11.0 +/- 3.1 vs. 14.1 +/- 2.01, p < 0.05). Hirudin disappearance rate was the same during high flux polysulfone Dialysis as during interdialytic periods. Hirudin removal was markedly higher in those patients still maintaining some residual renal function and parameters of hirudin removal were significantly correlated to residual creatinine clearance. It is concluded that hirudin removal from the body is markedly depressed in hemodialyzed end-stage renal failure patients and that even minor residual renal function may increase this removal rate.
Zbylut J Twardowski - One of the best experts on this subject based on the ideXlab platform.
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Update on cannulation techniques
Journal of Vascular Access, 2015Co-Authors: Zbylut J TwardowskiAbstract:There are two methods of fistula cannulation for hemoDialysis. The first, different site or rope-ladder cannulation method, established by originators of the arteriovenous fistula as a blood access for hemoDialysis in 1966, relies on changing the puncture sites for each Dialysis. The second, constant site or buttonhole method, developed several years later, recommends using the same puncture sites for consecutive dialyses. The first method is prevailing at present, but the second method is becoming more and more popular. The major advantage of this buttonhole method is lower cannulation pain, fewer fistula complications, with the exception of fistula infection, which is more common in some studies. This method is more difficult and requires experienced single cannulator to establish good puncture sites. Home hemoDialysis patients using single cannulator, the patient or helper, have better results with this method. Busy Dialysis centers with high rotation of cannulators do not have as good results and prefer the rope-ladder method.
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constant site buttonhole method of needle insertion for hemoDialysis
Dialysis & Transplantation, 2011Co-Authors: Zbylut J TwardowskiAbstract:Available data are suggesting that insertion of the hemoDialysis needles in exactly the same spot for consecutive dialyses (the “buttonhole” method) may be associated with fewer complications as compared with using different needle insertion sites for each Dialysis. The buttonhole method is becoming popular among home hemoDialysis patients. This paper will describe the origin of the method, early results, and the reasons why the method has not gained widespread popularity in U.S. hemoDialysis centers. Dial. Transplant. © 2011 Wiley Periodicals, Inc.
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synopsis from the article twardowski zj constant site buttonhole method of needle insertion for hemoDialysis Dialysis transplantation 1995 24 559 60 576
2005Co-Authors: Zbylut J TwardowskiAbstract:Overall fistula and graft survival depends on the quality of vessels, surgical technique, and the method of using the access. There is no generally accepted method for access puncture. An early recommendation was to change the site of puncture for each Dialysis to allow good healing of the puncture wound and avoid complications, such as hematoma at the puncture site, dilatation, stenosis, infection, and pseudoaneurysm. On the contrary, some data indicate that insertion of the hemoDialysis needles in exactly the same spot for consecutive dialyses may be associated with fewer complications when compared with different sites of needle insertion for each Dialysis. The initial experience with two methods based on almost ten thousand dialyses led to the following conclusions 1 : 1. Insertion into a previously-used site is easier and can be done very quickly, in less
Annemieke Dhondt - One of the best experts on this subject based on the ideXlab platform.
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Recombinant hirudin: clinical pharmacology and potential applications in nephrology.
BioDrugs : clinical immunotherapeutics biopharmaceuticals and gene therapy, 1999Co-Authors: Raymond Vanholder, Annemieke DhondtAbstract:The last decade has been characterised by the development of several anticoagulation methods as alternatives to the heparins. One of these is the antithrombin hirudin, which is now available on a large scale in the recombinant form. The application of hirudin as an anticoagulant in haemoDialysis has been complicated by the decrease of its clearance in patients with renal failure. The half-life of hirudin is more than 30 times longer in haemoDialysis patients than in healthy subjects. Therefore, at present, its use in the haemoDialysis setting is essentially limited to heparin-induced thrombocytopenia (HIT). Hirudin has been used sporadically and with success in nonrenal failure patients with HIT and at least once on a regular basis in a haemoDialysis patient. A starting dose between 0.08 and 0.15 mg/kg for the first Dialysis, followed by 50% of this quantity during the following dialyses is recommended. Hirudin activity can be monitored by aiming for threshold activated partial thromboplastin time (aPTT) values between 60 and 90 seconds, with urgent dosage adaptations once aPTT rises above 100 to 120 seconds. Hirudin concentrations during Dialysis should be maintained between 400 and 1000 microg/L, with determination by ecarin clotting time or chromogenic assays. At present, the use of hirudin is also limited by the absence of an effective antidote. In studies in humans, no enhanced removal of hirudin was observed during Dialysis with large pore dialysers in contrast to earlier published animal studies.
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pharmacokinetics of recombinant hirudin in hemodialyzed end stage renal failure patients
Thrombosis and Haemostasis, 1997Co-Authors: Raymond Vanholder, A Camez, Nic Veys, A Van Loo, Annemieke Dhondt, S RingoirAbstract:Recently, hirudin was used for the first time as an anticoagulant during hemoDialysis in men. Pharmacokinetic data of this compound in end-stage renal failure are however not available. In this study, the pharmacokinetics of recombinant hirudin (HBW 023) was evaluated in hemoDialysis-treated end-stage renal failure patients. HBW 023 was administered as a bolus at the start of a single Dialysis (0.02 to 0.08 mg/kg) in 20 patients, and plasma hirudin levels were followed during this and the 5 following dialyses, without additional hirudin administration. The initial Dialysis (HD1) was performed with a low flux polysulfone dialyzer, the following dialyses (up to HD6) with a high flux polysulfone dialyzer and regular heparin. Hirudin levels averaged 504.0 +/- 214.0 and 527.7 +/- 217.1 ng/ml in the middle and at the end of HD1, and then gradually decreased to 15.2 +/- 15.2 ng/ml at the end of HD6. Pharmacokinetic data were compared to those obtained in healthy controls (n = 5), receiving the same dose, and reaching the same peak hirudin level. Hirudin half-life was > 30 times longer in hemoDialysis patients (51.8 +/- 15.6 vs. 1.7 +/- 1.5 h, p 60 times higher (34,669 +/- 14,898 vs. 545 +/- 205 ng/ml x h, p < 0.001). Distribution volume was lower in hemoDialysis patients (11.0 +/- 3.1 vs. 14.1 +/- 2.01, p < 0.05). Hirudin disappearance rate was the same during high flux polysulfone Dialysis as during interdialytic periods. Hirudin removal was markedly higher in those patients still maintaining some residual renal function and parameters of hirudin removal were significantly correlated to residual creatinine clearance. It is concluded that hirudin removal from the body is markedly depressed in hemodialyzed end-stage renal failure patients and that even minor residual renal function may increase this removal rate.
