bluuebunny/crossref_metadata_2025 huggingface dataset:
Predilution Hemofiltration: A New Technology Applied to an Old Therapy
Authors: Ledebo I.
Published: March 2018

Postdilution hemofiltration (HF) as practised during the 80's is today associated with limitations of a medical, practical and economical nature. High blood flow rates are required to generate sufficient ultrafiltrate in order to achieve a clearance of small solutes comparable to hemodialysis within a reasonable time. High hematocrit and large body weight lead to extended treatment times. IV-quality solution is required in large volumes. This makes the use of bicarbonate difficult and has placed HF among the most expensive renal replacement therapies. These limitations can be resolved by performing HF in a predilution mode using an on-line prepared infusion solution. Diluting the blood before filtration increases the filtration fraction and the clearance of all solutes which are sieved by the membrane. Comparing pre- to postdilution at similar blood flow rates, the clearance may increase by 50% but three times as much infusion solution is required. To make predilution economically viable, the on-line preparation of the infusion solution is necessary, and this facilitates the use of bicarbonate. Compared to other dialysis therapies this new form of HF offers unequalled solute removal over a large molecular range.
A Comparison of the Effect of Enalapril and Metoprolol on Renal Function, Potassium Balance, Lipid Profile, Cardiac Function, Exercise Tolerance and Quality of Life in Hypertensive Dialysis Patients
Authors: Wong K.C. , Woo K.S. , Lam W.K. , Li K.T. , Lai K.N. , Nicholls M.G. , Lui S.F.
Published: March 2018

26 patients with hypertension while on hemodialysis or continuous ambulatory peritoneal dialysis for end-stage renal diseases were treated first with enalapril and then changed to metoprolol. Both drugs were shown to be similarly effective in controlling blood pressure. There was no difference between the two drugs in their effects on renal function, potassium balance, lipid profile, cardiac function, exercise tolerance, and quality of life. Mild worsening of anemia was observed during treatment with enalapril. No serious side effects were reported. Use of enalapril is safe in the treatment of hypertension in dialysis patients.
Mechanical Unloading Properties of Axial Flow Pumps and their Effect on Myocardial Stunning
Authors: Waldenberger F. R. , Meyns B. , Wouters P. , De Ruyter E. , Pongo E. , Flameng W.
Published: March 2018

Postischemic myocardial dysfunction affects morbidity and mortality in patients with coronary artery disease. It is known that mechanical unloading of the left heart ventricle can positively influence postischemic myocardial dysfunction. In this respect we tested two miniaturised axial flow pumps, i.e. the 14-F and the 21-F Hemopump®. An experimental study was carried out on 30 open chest sheep where regional myocardial wall motion was followed using sonomicrometry in a preparation of transient coronary artery occlusion. Only the larger 21-F Hemopump® showed hemodynamically significant unloading of the left ventricle. Furthermore, as far as stunning is concerned, systolic wall thickening recovered better when this type of pump was used during reperfusion. Also postejection thickening, which is an indication of diastolic postischemic dysfunction, is reduced significantly in the postischemic area (ANOVA, p<0.05). Thus, the 21F Hemopump®, but not the 14F Hemopump®, provides adequate mechanical unloading in order to beneficially influence myocardial stunning.
Resorbable Device for Fracture Fixation: In Vivo Degradation and Mechanical Behaviour
Authors: Fini M. , Giannini S. , Giardino R. , Giavaresi G. , Grimaldi M. , Aldini N. Nicoli , Orienti L. , Rocca M.
Published: March 2018

The availability of a high molecular weight poly(L-lactide), with supposed good mechanical properties, encouraged us to carry out an in vivo experimental study to evaluate the degradation rate and accompanying loss of strength during interaction with bone. Small cylindrical PLLA rods were manufactured by compression moulding. Thirty-six male New Zealand rabbits (b.w. 3 kg), randomly divided into six groups of six animals each, were submitted to implantation of the rods under general anaesthesia (0 3x7 mm rods in the lateral condylic region of the right femur and 0 3x50 mm rods in the intracondylic channel of the left femur). The animals were then sacrificed at the end of each experimental time (4, 8, 12, 24, 52, 64 weeks), hence the femurs were explanted. Histology showed no inflammatory cells with fragmentation or resorption of bone trabeculae. Mechanical studies showed a decrease in mechanical properties and flexional stiffness, and the absence of evident material resorption. Finally, the properties of this newly developed resorbable device, when confirmed, seem to justify future clinical introduction of this synthetic material.
Usefulness of Immunoadsorption Therapy for Systemic Lupus Erythematosus Associated with Transverse Myelitis. A Case Report
Authors: Taniguchi Y. , Yorioka N. , Okushin S. , Oda H. , Usui K. , Yamakido M.
Published: March 2018

Transverse myelitis (TM) is a very rare complication of systemic lupus erythematosus (SLE) and its prognosis is poor. It therefore needs to be treated aggressively. We describe a patient suffering from SLE associated with TM, who responded well to a combination of immunoadsorption therapy and steroid mini-pulse therapy. His serum interleukin 6 levels as well as clinical indicators fell to normal after this treatment.
Mass Transfer Limitations to the Performance of Membrane Bioartificial Liver Support Devices
Authors: Catapano G.
Published: March 2018

A number of membrane bioartificial devices have been proposed for liver support. However, their design does not yet ensure the successful treatment of acute liver insufficiency. In this paper, the Author reviews the limitations of the mass transport phenomena to the performance of a membrane bioartificial liver support device. First of all the requirements that an optimal membrane bioartificial liver support device has to meet for the therapy to be effective are presented. On these grounds, the issues that are still to be addressed to optimize the performance of such devices are discussed: particular attention is devoted to the mass transport phenomena in each region of the membrane bioartificial device. Finally, the main transport features of the membrane bioartificial liver support devices proposed so far are illustrated and examined.
The Effect of Oxygen Transport Resistances on the Viability and Functions of Isolated Rat Hepatocytes
Authors: Catapano G. , De Bartolo L. , Lombardi C.P. , Drioli E.
Published: March 2018

The treatment of fulminant hepatic failure with a bioartificial liver support device relies on the possibility of replacing the detoxification and synthetic functions of the injured liver for as long as needed for patient recovery. In spite of progress in cell culture techniques, the effective use of isolated hepatocytes in liver support devices is currently hampered by a lack of information on the metabolic factors limiting long term hepatocyte culture. In this paper, we report our investigation on the effects of oxygen transport resistances on the viability and functions of isolated rat hepatocytes cultured on collagen coated Petri dishes. Detoxification and synthetic functions of the hepatocytes were studied with respect to ammonia and phenolsulphonphthalein elimination and urea synthesis. Lower resistances to oxygen transport favored hepatocyte survival. The isolated hepatocytes synthesized urea at rates that decreased as the resistance to oxygen transport increased. The rate at which urea was synthesized also decreased during the culture. Neither PSP, nor ammonia elimination rate was greatly affected by increasing oxygen transport resistances and remained rather constant up to a week of culture.
Matrix-Induced Liver Cell Aggregates (MILCA) for Bioartificial Liver Use
Authors: Kong L B. , Chen S. , Demetriou A.A. , Rozga J.
Published: March 2018

Ex vivo reproduction of liver microstructure using isolated hepatocytes is critical for bioartificial liver use. We have developed a method of producing matrix-induced liver cell aggregates (MILCA) using a small number of collagen-coated beads as a nidus for formation of hepatocyte aggregates. Porcine hepatocytes were obtained by EDTA/collagenase digestion. Cell viability was assessed by trypan blue exclusion and LDH release. Cytochrome P-450 activity was determined at 4 and 24 hours by measuring the formation of 7-hydroxycoumarine (7-HC) from 7-ethoxycoumarine (7-EC). At 4 hours, the viability of MILCA was 92±2%, LDH release was 100+22 U/L and 7-HC formation was 140±34 nM/g cells. At 24 hours, MILCA viability remained greater than 90%, but 7-HC formation was lower than that of parallel control monolayer hepatocyte cultures (194±43 vs 481±78 nM/g cells; p<0.002). On transmission electron microscopy, MILCA ultrastructure resembled that of a normal liver (maintenance of cell polarity, gap junctions, bile canaliculi, intact organellae, glycogen granules). MILCA were subsequently inoculated into hollow-fiber bioreactors which were perfused for 6 hours with plasma recovered from patients with fulminant hepatic failure (n=6; 5x109 cells/cartridge, recirculation of 350 ml of plasma at 400 ml/min). In these studies, lidocaine (20 μg/ml) was cleared in less than 3 hours and 7-HC production at 6 hours was 71+8 nM/g cells. Other MILCA effects noted in this system included lowering of plasma lactate, bilirubin and ammonia and increase in the level of several non-essential amino acids.
Modulation of CD11b/CD18 on Monocytes and Granulocytes following Hemodialysis Membrane Interaction in vitro
Authors: Thylén P. , Fernvik E. , Lundahl J. , Hed J. , Jacobson S.H.
Published: March 2018

We studied the generation of CD11b/CD18 mobilizing factors in serum after incubation with dialysis membrane fragments of different chemical composition. We also evaluated the relative importance of the alternative and classical pathways of the complement system in the generation of such factors. Monocytes and granulocytes from healthy blood donors were incubated in normal human serum (NHS) and in NHS that had been preincubated with Cuprophan (CU) membrane (NHS-CU), Hemophan (HE) (NHS-HE) or polysulfone (PS) (NHS-PS). NHS-CU caused the highest up-regulation of the CD11b/CD18 receptor on monocytes and granulocytes. The rank in capacity to mobilize CD11b/CD18 on granulocytes was CU>HE>PS (p<0.001), CU>HE (p<0.05) and HE>PS (p<0.001). The rank in capacity to mobilize CD11b/CD18 on monocytes was CU>HE>PS (p<0.001), CU>HE (p<0.05) and HE>PS (p<0.01). NHS-PS induced a lower up-regulation of CD11b/CD18 compared to NHS which indicates that serum factors with the ability to mobilize the CD11b/CD18 receptor on monocytes and granulocytes are deposited on or adsorbed by PS. In order to study the relative contribution of the alternative and classical pathways of the complement system in the generation of CD11b/CD18 mobilizing factors in serum, three different serum preparations (1. both pathways intact. 2. only the alternative intact and 3. only the classical pathway intact) were used. The CU membrane activated the classical pathway to a larger extent than the PS membrane (p<0.01). When only the alternative pathway was intact no difference in the generation of CD11b/CD18 mobilizing factors between the CU and PS membranes was observed. These studies show that CD11b/CD18 mobilizing serum factors are generated after incubation with CU membranes and that such factors are probably adsorbed by PS. The classical pathway of complement activation seems to contribute to the generation of CD11b/CD18 mobilizing factors in serum.
Design of a Physiologic Pulsatile Flow Cardiopulmonary Bypass System for Neonates and Infants
Authors: Ündar A. , Runge T.M. , Miller O.L. , Felger M.C. , Lansing R. , Korvick D.L. , Bohls F.O. , Ottmers S.E. , O'dell B.J. , Ybarra J.R. , Howelton R.V. , Mireles R.Z. , Benson C.K. , Holland M.C. , Calhoon J.H.
Published: March 2018

Cardiopulmonary bypass surgical techniques that allow a surgeon to operate on the infant's heart use an extracorporeal circuit consisting of a pump, oxygenator, arterial and venous reservoirs, cannulae, an arterial filter, and tubing. The extracorporeal technique currently used in infants and neonates is sometimes associated with neurologic damage. We are developing a modified cardiopulmonary bypass system for neonates that has been tested in vitro and in one animal in vivo. Unlike other extracorporeal circuits which use steady flow, this system utilizes pulsatile flow, a low prime volume (500ml) and a closed circuit. During in vitro experiments, the pseudo patient's mean arterial pressure was kept constant at 40 mmHg and the extracorporeal circuit pressure did not exceed a mean pressure of 200 mmHg. In our single in vivo experiment, the primary objective was to determine whether physiologic pulsatility with a 10F (3.3 mm) aortic cannula could be achieved. The results suggest that this is possible.
Small Pore Size Microporous Membrane Oxygenator Reduces Plasma Leakage during Prolonged Extracorporeal Circulation: A Case Report
Authors: Musch G. , Verweij M. , Bombino M. , Banfi G. , Fumagalli R. , Pesenti A.
Published: March 2018

Plasma leakage has been regarded as the main technical problem during prolonged extracorporeal circulation (ECC) with microporous membrane oxygenators (MMOs). We report the case of a 15 year old male who underwent long term ECC for ARDS and in whom, by using new MMOs with reduced pore size, we were able to achieve prolonged artificial gas exchange efficiency with minimal plasma leakage. We conclude that reduced pore size MMOs might represent a valuable technical advance in extracorporeal oxygenation therapy.
Variation in Artificial Heart Acceleration and Sound Production with Prosthetic Valve Selection in vitro
Authors: Pantalos G.M. , Kim C.H. , Flatau A.
Published: March 2018

In an attempt to explore methods to reduce total artificial heart (TAH) acceleration and sound production, in vitro measurements of TAH acceleration and sound were made when using a variety of prosthetic valves in a test ventricle. A miniature, uniaxial, high fidelity accelerometer was glued to the housing of a UTAH-100 left ventricle adjacent to the inflow and outflow ports and parallel to the axis of diaphragm excursion. A miniature, high fidelity contact microphone was glued to the opposite side of the ventricular housing between the inflow and outflow ports. Data was collected over a range of heart rates, ventricular filling volumes and control modes while using tilting disc valves (TDV) and polymer trileaflet valves (PTV). For both valve types, the peak systolic acceleration impulse was lower (≈ 50%) when the ventricle was fully rather than partially filled and the peak diastolic acceleration impulse was lower (≈ 50%) when the ventricle was fully rather than partially ejected. The magnitude of the acceleration with PTVs was ≈ 20x less than the TDVs (0.5 to 2.2 g vs. 10 to 49g). The magnitude of the sound production was also considerably less with the PTVs (28 to 49 db vs. 50 to 64 db). Diastolic acceleration and sound production was approximately twice the systolic value for the TDVs; the reserse was true for PTV sound production. These data demonstrate the substantial reduction in TAH impulse acceleration and sound production by selecting PTVs over TDSs. With PTVs, the TAH impulse acceleration is the same as the natural heart. Consequently, this ability to lower TAH acceleration and sound production to the level of the natural heart may lead to a reduction in component wear, patient discomfort and other undesirable consequences of TAH implantation.
Peritonitis Caused by Monilia sitophila in a Patient Undergoing Peritoneal Dialysis
Authors: Radix A.E. , Bieluch V.M. , Graeber C.W.
Published: March 2018

Fungi have become an increasingly important cause of peritonitis in patients undergoing continuous ambulatory peritoneal dialysis. The most common cause of fungal peritonitis is Candida. However, in recent years unusual and “nonpathogenic” fungi have been reported as etiologic agents of CAPD-associated peritonitis. We are reporting the first case of CAPD-associated peritonitis caused by Monilia sitophila. This organism had previously been considered to be non-pathogenic, and a troublesome laboratory contaminant. Our patient was successfully managed with intravenous and intraperitoneal amphotericin B, followed by oral itraconazole, without removal of her Tenckhoff catheter.
A New Polymethylmethacrylate Membrane for Hemodialysis
Authors: Bonomini M. , Fiederling B. , Bucciarelli T. , Manfrini V. , Di Ilio C. , Albertazzi A.
Published: March 2018

High molecular weight (MW) solutes are not removed during conventional hemodialysis (HD), and their accumulation is thought to play a role in some long-term HD complications (anemia, bone and joint pain, neuropathy, itching). The present trial was conducted to evaluate the removal capacity during in vivo HD of a new polymethylmethacrylate (PMMA) membrane (Filtryzer BK-F, 1.3 m2) compared to conventional PMMA (BK-P, 1.6 m2) and to cellulose acetate (CA, 1.3 m2). BK-F dialyzers, with a pore size of 100 A° and 62% porosity, are designed to remove high MW substances. Ten stable anuric RDT patients (53 ± 13 years) were treated for one week with each membrane in a randomized sequence. Plasma concentrations of creatinine, BUN and beta2-microglobulin (beta2-M) were measured before (b) and after (a) HD to determine the reduction rate for these substances (%). Beta2-M concentration after HD was corrected for changes in distribution volume. Samples of spent dialysate were collected after 3 minutes, 120 minutes and at the end of HD sessions, and appropriately treated and concentrated for HPLC analysis. The reduction rate for BUN and creatinine was similar for the 3 membranes. BK-F showed a higher beta2-M reduction rate than BK-P (p<0.005) or CA (p<0.0001). HPLC analysis of dialysate showed prevalent peaks < 4 kilodaltons (kDa) throughout HD for BK-P and CA. Solutes > 10 kDa were infrequently detected. Peak profile during HD with BK-F was quite different, showing a predominant peak > 50 kDa which also included albumin. However, albumin loss significantly decreased after 120 minutes and at the end of dialysis compared with the 3-minute values, and was lower than that reported in CAPD patients. With BK-F a peak of MW > 500 kDa was also detected which previous studies indicated as a range characterized by the presence of erythropoiesis inhibitors. Use of the BK-F membrane in HD could afford satisfactory removal of high MW substances, thereby preventing or controlling some long-term HD complications such as anemia or beta2-M amyloid formation.
The Effect of Catabolite Concentration on the Viability and Functions of Isolated Rat Hepatocytes
Authors: Catapano G. , DE Bartolo L. , Lombardi C.P. , Drioli E.
Published: March 2018

The treatment of patients with hepatic failure by means of hybrid liver support devices using primary xenogeneic hepatocytes is currently hindered by the rapid loss of cell metabolic functions. Similarly to what happens with other mammalian cells, accumulation of catabolites in the neighborhood of cultured hepatocytes might significantly affect their viability and functions. In this paper, we investigated the effects of high concentrations of catabolites, such as ammonia and lactic acid, on the viability and functions of rat hepatocytes cultured on collagen coated Petri dishes. The effects on hepatocyte functions were established with respect to their ability to synthesize urea and to eliminate ammonia. Indeed, high catabolite concentrations effected both hepatocyte viability and functions. The number of viable hepatocytes decreased with increasing ammonia concentrations in the culture medium. High ammonia concentrations had also both an inhibitory and a toxic effect on hepatocyte functions. In fact, the hepatocytes synthesized urea and eliminated ammonia at rates that decreased with increasing ammonia concentrations. Similarly, high lactic acid concentrations were toxic to the cells and also inhibited their synthetic functions.
Cytokine Production by Human Peripheral Blood Mononuclear Cells Stimulated by a Pseudomonas Aeruginosa Culture Filtrate: Role of Plasma and Polymyxin B
Authors: Sundaram S. , Barrett T.W. , Butt N.K. , Porat R. , King A.J. , Pereira B.J.G.
Published: March 2018

The lack of consensus regarding the significance of transmembrane passage of bacterial products across hemodialysis membranes can be related to several methodological differences in the various studies, including the choice of circulating fluid in the blood compartment of the model, nature and concentration of the bacterial products employed to challenge the dialysate compartment and whether cytokine production by PMBC or the limulus amebocyte lysate (LAL) assay was used as the index of transfer and the cytokine used as the read-out. In this study, we examined the production of interleukin-1 alpha (IL-1α), interieukin-1 receptor antagonist (IL-1Ra) and interleukin-8 (IL-8) by peripheral blood mononuclear cells (PBMC) incubated with a Pseudomonas aeruginosa culture filtrate. Further, the effects of 10% autologous human plasma and Polymyxin B sulfate (PmB) on cytokine production by PBMC were also characterized. The results of our study indicate that the Ps. aeruginosa culture filtrate had both PmB suppressible and PmB non-suppressible components and that the addition of 10% human plasma significantly enhanced cytokine production by both PmB suppressible and PmB non-suppressible components. The enhancing effect of plasma was most evident at low concentrations of the filtrate. The inhibitory effect of PmB was most evident in samples cultured in the presence of 10% plasma. There was a direct correlation between the production of IL-1α and IL-1Ra suggesting that both pro-inflammatory cytokines and cytokine-specific inhibitory proteins are concurrently produced. There results have direct relevance to selection of study conditions for in vitro models used to study the transmembrane passage of bacterial products across hemodialysis membranes
Reduction of Platelet Trapping in Membrane Oxygenators by Transmembraneous Application of Gaseous Nitric Oxide
Authors: Keh D. , Gerlach M. , Kürer I. , Falke K.J. , Gerlach H.
Published: March 2018

Bleeding during extracorporeal circulation (ECC) is often induced and/or aggravated by thrombocytopenia due to platelet-trapping in hollow fiber membrane oxygenators (HFMO). Nitric oxide (NO) has platelet anti-aggregating and dis-aggregating properties. In a paired system we tested whether gaseous NO, added to the gas compartment of one of two parallel running heparin-bonded HFMO attenuated platelet-trapping. Platelet consumption was markedly reduced in the NO-treated HFMO. These data strongly indicate that the application of gaseous NO could prove a new therapeutical approach to reduce bleeding during ECC, serving as a new way of preventing platelet loss, thus reducing the need for high systemic heparinization.
Large-Scale Preparation and Function of Porcine Hepatocyte Spheroids
Authors: Sakai Y. , Naruse K. , Nagashima I. , Muto T. , Suzuki M.
Published: March 2018

To obtain a large number of porcine hepatocyte aggregates (spheroids) that have great potential in a bioartificial liver (BAL), we performed spheroid formation at a high cell density in a 1-L-scale spinner flask fitted with a silicon tubing apparatus for oxygen supply. We thereby obtained, within 24 hours, approximately fifty times more porcine hepatocyte spheroids as compared with the results of previous reports. The amount obtained corresponds to 2.5×109 cells and to roughly one-sixth of the cell number required for a BAL for a human patient. When we cultured spheroids continuously in suspension, they expressed three times more albumin secretion and twice the ammonium removal as compared with conventional monolayers during 10 days culture. Collagen gel entrapment of spheroids particularly lowered albumin secretion. We therefore conclude that the supension culture vessel of porcine hepatocyte spheroids is one of the most promising module types.
Strange Hemodynamic Attractor Parameter with 1/R Total Artificial Heart Automatic Control Algorithm
Authors: Yambe T. , Abe Y. , Yoshizawa M. , Imachi K. , Tabayashi K. , Takayasu H. , Takeda H. , Gouhara K. , Nitta S.
Published: March 2018

To evaluate the automatic control algorithm of the total artificial heart (TAH) as an entity, and not just as parts, a non-linear mathematical analyzing technique including chaos theory was utilized. Chronic experiments on the biventricular bypass type artificial heart implantation were performed in healthy adult goats after the natural ventricles were removed. Hemodynamic time series data were recorded under the awake standing condition with TAH 1/R and fixed driving. Time series data were recorded on a magnetic tape and analyzed on a personal computer system with an A-D converter. Using the nonlinear mathematical technique, the time series data were embedded into the phase space and the Lyapunov numerical method was carried out for the quantitative evaluation of the sensitive dependence on the initial condition of the reconstructed attractor. Calculation of the largest Lyapunov exponents suggested that the reconstructed attractor of the left pump output during TAH 1/R control was a larger dimensional strange attractor, a characteristic pattern of deterministic chaos. A total system indicating chaotic dynamics was thought to be a flexible and intelligent control system. Thus, our results suggest that 1/R TAH control may be suitable for the biventricular assist type total artificial heart.
Primary Graft Failure after Heart Transplantation. Successful Recovery with Pneumatic Biventricular Assistance
Authors: Fernandez A.L. , Herreros J.M. , Llorens R. , Martinez A. , Panizo A. , Manito N.
Published: March 2018

A 41-year-old male underwent orthotopic heart transplantation complicated by intraoperative acute allograft failure. The patient required immediate placement of a pneumatic biventricular assist device which was kept for 49 days until graft recovery resulted in successful explantation of the device. The patient was discharged from hospital on postoperative day 112. Management of primary cardiac allograft failure with mechanical ventricular assistance is discussed
Protein a Carrying Monosize PMMA Microbeads for the Removal of HlgG from Human Plasma
Authors: Pişkin E. , Ayhan H. , Bulmuş E.V. , Rad A.Y. , Falkenhagen D. , Weber C.
Published: March 2018

Protein A-incorporated polymethylmethacrylate (PMMA) microbeads were investigated for specific removal of HlgG from human plasma. The microbeads were prepared by a phase inversion polymerization, and activated by periodate oxidation. Protein A was then incorporated by covalent binding onto these microbeads through hydroxyl groups coming from the stabilizer. The amount of incorporated protein A was controlled by the initial concentrations of protein A in the immobilization medium and pH. The maximum protein A immobilization of 0.615 mg protein A/g PMMA, was observed at a pH of 9.5 corresponding to an initial protein A concentration of 0.1 mg/ml. There was no HlgG adsorption onto the plain PMMA microbeads, while high HlgG adsorptions of up to 32 mg HlgG/g PMMA were achieved with human plasma.
Comparative Study on Reused Haemodialysis Membranes
Authors: Sótonyi P. , Jàray J. , Pàdàr Z. , Woller J. , Füredi S. , Gàl T.
Published: March 2018

Data have shown that on the internal surface of reused haemodialysis membranes complement elements of plasma proteins, cells and cellular debris from the patient's blood are deposited. The aim of our study was to identify the effect of reuse on the haemodialysis membrane surface. Original and reused haemodialysis membranes were studied by the methods of light, transmission and scanning electron microscopy, immuno-histochemistry and X-ray spectrum element analysis. With reuse the membrane surface becomes uneven, and its continuity may break. Plasma protein and cellular elements are deposited on the damaged surface following continued reuse. Presence of IgM deposists were confirmed by immunohistochemical observation. Moreover, following reuse the X-ray spectrum analysis verified structural changes in the haemodialysis tube compared to the control material; accumulated aluminium, silicon, phosphorus, sulphur and chlorine were detected on the wall of the dialysis membrane
A Simple Mathematical Model of Intradialytic Sodium Kinetics: “in vivo” Validation During Hemodialysis with Constant or Variable Sodium
Authors: Ursino M. , Colì L. , La Manna G. , Cicilioni M. Grilli , Dalmastri V. , Giudicissi A. , Masotti P. , Avanzolini G. , Stefoni S. , Bonomini V.
Published: March 2018

A simple mathematical model of the intradialytic relationship between natraemia and dialysate sodium concentration is presented. The model includes a bicompartmental description of sodium, urea and fluid kinetics and an algebraic characterization of diffusive/convective mass-transfer across the dialysis membrane. Its ability to provide realistic responses has been validated comparing model predictions by a priori parameter tuning against quantities measured during in vivo sessions with both constant and variable dialysate sodium concentration. A quantitative analysis of model predictions indicates that the mean deviation between data calculated by the model and those measured in vivo is 1.32 mEq/l for sodium and 0.76 mmol/l for urea, values which do not greatly exceed the measurement errors of current instruments. The model's predictive capacity thus proves reliable. The ability of the model to calculate the amount of sodium removed and the time course of intra-extracellular volumes during the dialysis session makes it possible to forecast the patient's clinical tolerance to a given sodium dialysate concentration.
Extracorporeal Artificial Liver: The Influence of a Second Cell Layer on the Morphology and Function of Immobilized Human Hepatocytes
Authors: Wick M. , Koebe H.G. , Schildberg F.W.
Published: March 2018

Hepatocytes in long-term cultures represent a promising approach to preserve liver function under standard culture conditions. Hepatocyte cultures as the key components in an extracorporeal artificial liver (EAL) in the treatment of hepatic insufficiency, would be a great advantage. However, one of the numerous unsolved problems is the limitation of the surface area of a future EAL. To decrease the dimensions of same, we modified the cell immobilization technique by placing a second layer of immobilized human hepatocytes onto a layer of pre-immobilized hepatocytes creating a “sandwich immobilization” (SI) system. Immobilization and sandwich immobilization were compared over an investigation period of 30 days: functional performance mirrored by cholinesterase (CHE) and albumin secretion showed remarkable differences only in the course of the first week, whereas we found almost no differences from day 8 on. The total DNA-values on days 0, 1, 7, 14, 21 and 30 varied strongly after the first week but were very similar up to day 30. Finally, it appears disadvantageous to enlarge number/cm2 of (human) hepatocytes in long-term cultures or for application in an EAL by means of sandwich immobilization.
Left Intraventricular Balloon Pump Optimization during Intractable Cardiac Arrest
Authors: Stamatelopoulos S.F. , Kochilas L. , Saridakis N.S. , Zakopoulos N.A. , Moulopoulos S.D.
Published: March 2018

This work aims to determine optimal balloon shape and volume during left intraventricular balloon pumping (IABP) in the fibrillating dog heart. A balloon volume equal to the left ventricular end-diastolic volume (LVEDV) maintained a higher systolic aortic pressure and flow (106.4 ± 2.7 mmHg and 84.7 ± 2.35 ml/kg/min, x ± SEM, respectively) than a 25% smaller (97.8 ± 3.3 mmHg, P=0.002 and 63.7 ± 4.1 ml/Kg/min, P=0.002, respectively) or a 25% larger balloon (87.4 ± 2.3 mmHg, P=0.002 and 70.9 ± 3.4 ml/kg/min, P=0.002, respectively). Among 5 different balloon shapes tested, a pear-shaped balloon inflated from the apex to the base of the left ventricle induced the highest (P varying from 0.042 to 0.01, compared to the remaining balloon shapes) systolic aortic pressure and flow (104.6 ± 4.5 mmHg and 77.9 ± 1.7 mg/kg/min, respectively). In conclusion, a pear shaped balloon, inflated to a volume equal to the LVEDV, from the apex to the base of the left ventricle, induced an optimal hemodynamic effect during LVBP.
The Fresenius Continuous Autotransfusion System (CATS): Preliminary Studies and Application
Authors: Florio G. , Valbonesi M. , Lercari G. , Frisoni R. , Polucardo N. , Beraudo S.
Published: March 2018

A new CFC apparatus for intraoperative blood salvage (CATS) has been introduced by Fresenius and submitted to preliminary evaluation at our hemapheresis unit. The volume of shed blood submitted to washing was 1714 ± 496 with a hematocrit of 19% and the volume of PRBC ready for transfusion 297.9 ml with hematocrit of 64.3%. Elimination of contaminant activated platelets and WBC was 92% and 74% respectively. Elimination of contaminants such as protein, free hemoglobin, LDH and K ions was always over 95%. Regular application of CATS is warrented after our study.
Arteriovenous Fistula Obstruction and Expression of Platelet Receptors for Von Willebrand Factor and for Fibrinogen (Glycoproteins GPIb and GPIIb/llla) in Hemodialysis Patients
Authors: Liani M. , Salvati F. , Tresca E. , Paolo G. Dl , Vitacolonna L. , Golato M. , Velussi C.
Published: March 2018

Platelet surface receptors for von Willebrand factor and for fibrinogen (glycoproteins GPIb and GPIIb/llla) were studied with monoclonal antibodies CD42 and CD41 and cytofluorometry in 31 healthy subjects, 10 hemodialysis patients with no A-V fistula obstruction (patent original fistula), 10 hemodialysis patients with frequent A-V fistula obstruction (more than twice), 12 patients with mild chronic renal failure (creatinine 1.75±0.40 mg/100ml), 11 patients with advanced chronic renal failure (creatinine 5.62±1.22 mg/100ml), and 10 patients with end-stage renal disease (ESRD) treated with peritoneal dialysis. There was a significant increase of platelet surface glycoproteins GPIb and GPIIb/llla in the population of hemodialysis patients with frequent A-V fistula obstruction. The expression of these platelet receptors might be related to the prothrombotic tendency of a group of patients with ESRD, who suffer more occlusive and thrombotic events of the A-V fistula. This group of patients may also have a higher frequency of systemic thrombotic and atherosclerotic complications.
Biological Evaluation of Mechanical Circulatory Support Systems in Calves
Authors: Rakhorst G. , Van Der Meer J. , Kik Ch. , Mihaylov D. , Havlik P. , Trinkl J. , Monties J.R.
Published: March 2018

Data from animal experiments with mechanical circulatory support systems (MCSS) performed in Groningen and Marseille over the past years were used to obtain normal values of hematological, coagulation, rheological and blood chemistry parameters in calves. These parameters were divided between two groups: a limited number of parameters necessary to assess biocompatibility properties of MCSS quickly and a more extensive number of parameters suitable for more detailed biological evaluation of blood pumps. All applied tests can be examined in calf blood as well as in human blood. Parameters were selected on clinical relevance and usefulness for standardization procedures. The obtained data were compared with normal values in human beings derived from the literature.
Autonomic Neuropathy in Hemodialysis Patients Treated with Recombinant Human Erythropoietin
Authors: Stojcheva-Taneva O.O. , Polenakovic M.H.
Published: March 2018

Autonomic nervous system (ANS) function was evaluated in hemodialysis patients treated with recombinant human erythropoietin (rHu-EPO) before and after therapy, in an effort to evaluate the role of anemia in the genesis of autonomic dysfunction in chronic renal failure (CRF). Studies were conducted using a battery of five cardiovascular reflex tests: Valsalva maneuver, handgrip exercise, heart rate response to standing (30:15 index), post-Valsalva rise in blood pressure and postural drop in blood pressure. The patients were divided into two groups: group I consisted of 14 patients on maintenance hemodialysis treated with rHu-EPO for one year, and group II - 13 hemodialysis patients treated with rHu-EPO for two years. The results of the tests were compared before and after the correction of anemia by rHu-EPO in each group, as well as with the control group of ten healthy subjects. Data show that renal anemia is not implicated in the genesis of ANS dysfunction in hemodialysis patients, since correction of same by rHu-EPO does not improve the autonomic dysfunction.
Blood Contact with Artificial Surfaces during BVAD Support
Authors: Hasper D. , Hummel M. , Hetzer R. , Volk H.D.
Published: March 2018

Persistently elevated levels of cytokines (IL-6, IL-8) during the course of mechanical circulatory support correlate well with fatal outcome. To determine the influence of blood/artificial surface interaction on the chronic inflammatory process, we studied the biocompatibility of silicone and polyurethane membranes in vitro. Cultures of isolated mononuclear cells or whole blood were incubated for 24 hours in tubes coated with silicone or polyurethane, both used in the construction of ventricular assist systems. Concentrations of several inflammatory mediators were measured in the supernatant. Our results can be summarized as follows: a) Monocytes were stimulated to release inflammatory cytokines like IL-8 and MIP-1α, particularly when silicone was involved; b) Both silicone and polyurethane stimulated thrombocytes thus resulting in the release of P-Selectin and PDGF-AB, although polyurethane was a stronger stimulus; c) Moderate complement activation was triggered by contact with either of the artificial surfaces. However, the prevention of most of these effects by coating the artificial surface with protein and the lack of correlation between in vitro data and serum levels of IL-6 and IL-8 during the course of circulatory support suggest that the persistence of inflammatory cytokines during BVAD support is not caused by blood/surface interaction.
Comparison of Hollow Fibre Membranes for Hepatocyte Immobilisation in Bioreactors
Authors: Gerlach J.C. , Schnoy N. , Vienken J. , Smith M. , Neuhaus P.
Published: March 2018

Various hollow fibre membranes of polyamide, cellulose and polypropylene were investigated as potential substrata for hepatocyte immobilisation in bioreactors for hybrid liver support systems. Membranes were subjected to a cytocompatibility test in which the attachment and morphology of primary hepatocytes were evaluated. The effect of coating with collagen and fibronectin was also studied. Adequate cell immobilisation was possible on polypropylene and polyamide membranes even without coating. The flattening process of the cells was dependent on the material and the coating. The incorporation of porous polypropylene and polyamide hollow fibres in hybrid liver cell bioreactors and their specific permeability properties could also offer means for cell oxygenation, metabolite distribution and immuno-isolation purposes.
Arteriosclerosis in Dialysis Patients
Authors: Bommer J. , Strohbeck E. , Goerich J. , Bahner M. , Zuna I.
Published: March 2018

Arteriosclerosis is a constant problem in long-term hemodialysis patients. Computer tomography of the abdominal aorta allows a well-defined and reproducible evaluation of aortosclerosis. In the cross-sectional study, aortosclerosis was significantly accelerated in 84 chronic hemodialysis patients and was comparable to the results found in 20-year older control patients without renal disease. The increase of aortosclerosis correlated significantly with age of the patient, smoking, and duration of dialysis therapy. Furthermore, increased VLDL cholesterol and decreased HDL cholesterol seem to enhance aortosclerosis in our dialysis patients. In the longitudinal study (two CT scans with a time interval of 87 ± 62.7 months) in 36 dialysis patients, progressed aortosclerosis correlated significantly with the long duration of hypertriglyceridemia, VLDL cholesterol, uric acid, and calcium phosphate products. Progression of aortosclerosis was reduced in parathyroidectomized patients. The study suggests that premature aortosclerosis is found in dialysis patients. In addition to the common risk factor of aortosclerosis, disturbed calcium phosphate and parathyroid hormone metabolism seem to enhance aortosclerosis in patients under maintenance hemodialysis.
Consideration of Potential Immunological Problems in the Application of Xenogenic Hybrid Liver Support
Authors: Bornemann R. , Smith M.D. , Gerlach J.C.
Published: March 2018

Hybrid liver support systems (LSS) for the use of pig liver cells are under development for extracorporeal therapy of acute liver failure and for bridging to liver transplantation. A literature overview about possible immunological side effects of a clinical application is given. The data summarised from experimental studies and those clinical applications of porcine cells reported so far, suggest that clinical use of LSS utilising porcine cells and an immuno-isolation membrane should not be compromised by severe immunological complications. The reported data suggest that clinical application should be conducted in conjunction with carefully planned immunological monitoring. Only after such applications of LSS have been carried out and further data have been evaluated, might one be able to judge the immunological consequences of broader application of hybrid liver support.
Clinical Experience with a Porcine Hepatocyte-Based Liver Support System
Authors: Chen S.C. , Hewitt W.R. , Watanabe F.D. , Eguchi S. , Kahaku E. , Middleton Y. , Rozga J. , Demetriou A.A.
Published: March 2018

The only clinically proven effective treatment of fulminant hepatic failure (FHF) is orthotopic liver transplant (OLT). However, many patients die before an organ becomes available. Thus, there is a need for development of an extracorporeal liver support system to “bridge” these patients either to OLT or spontaneous recovery. We developed a bioartificial liver (BAL) based on plasma perfusion through a circuit of a hollow-fiber cartridge seeded with matrix-anchored porcine hepatocytes to treat patients with severe acute liver failure. Two groups of patients were studied. Group 1 (n = 12): patients with FHF. All patients were successfully “bridged” to OLT. “Bridge” time to OLT was 21-96 hr (mean: 39.3 hr). All patients were discharged neurologically intact. Reversal of decerebration was noted in all 11 deep stage 4 coma patients. There was reduction in intracranial pressure (ICP mmHg, 18.2 ± 2.2 to 8.5 ± 1.2; p<0.004) and increase in cerebral perfusion pressure (CPP mmHg, 71.1 ± 4.0 to 84.7 ± 2.6; p<0.006). Laboratory values pre- and post- BAL treatment: glucose (mg/dl) 122 ± 11 to 183 ± 21, p<0.002; ammonia (μmol/l) 155.6 ± 13.2 to 121.6 ± 9.5, p<0.02; total bilirubin (mg/dl) 21.6 ± 2.8 to 18.2 ± 2.2, p<0.001; PT (sec) 23.2 ± 1.7 to 21.9 ± 1.0, p<0.3. Group II (n=8): patients with chronic liver failure experiencing acute exacerbation. Two patients survived and later underwent OLT. Six patients (not OLT candidates) died 1-14 days after last BAL treatment. Laboratory values pre- and post-treatment: ammonia (μmol/l) 201 ± 47 to 143 ± 25, p<0.06; total bilirubin (mg/dl) 22.8 ± 5.2 to 19.5 ± 4.4, p<0.01; PT (sec) 22.5 ± 2.0 to 21.8 ± 1.1, p<0.6. Conclusion: our clinical experience with the BAL suggests that it may serve as “bridge” to OLT in patients with FHF primarily by reversing intracranial hypertension, but it is not a substitute for OLT in patients with end-stage liver disease who are non-transplant candidates.
Effects of a pH 7.4, lactate-based and a pH 7.4, bicarbonate-based peritoneal dialysis solutions on neutrophil superoxide generation
Authors: Ing T.S. , Patel B.P. , Patel J.A. , Patel N.K. , Yu A.W. , Osman A. , Zhou F.Q.
Published: March 2018

Neutrophil superoxide formation was similar when cells were incubated in self-made, non-autoclaved, pH 7.4, lactate-based peritoneal dialysis solutions or in their self-made, non-autoclaved, pH 7.4, bicarbonate-based counterparts. On the other hand, commercially available, autoclaved, pH 7.4, lactate-based peritoneal dialysis solutions resulted in inhibition of superoxide production when compared to their self-made, non-autoclaved, pH 7.4, lactate-based or bicarbonate-based counterparts. The cause for this inhibition of superoxide generation is at present unknown.
A new polymer valve for mechanical circulatory support systems
Authors: Suh S.W. , Kim W.G. , Kim H.C. , Min B.G.
Published: March 2018

A new low-cost artificial heart valve with easily modified dimensions according to its application was developed using segmented polyurethane (SPU). It consists of a convex frame and a concave membrane which floats in the center of the frame while working. The hydrodynamic performance of the polymer valve was compared with that of the Björk-Shiley mechanical valve using a mock circulatory testing system. The hydrodynamic performance of this valve was superior to the Björk-Shiley mechanical valve. The valve was applied to a ventricular assist device (VAD) developed in our institute. In vivo performances of these systems were tested using mongrel dogs. During the experiments, there were no complications related to malfunction of the valve. At postmortem examinations, no thrombus formation was found on the valve surface, and no embolus was detected in the kidneys. We believe this valve could prove a very useful alternative for valves of mechanical circulatory support systems (MCSS) such as VAD and TAH.
A computer controlled pulsatile pump: preliminary study
Authors: Zwarts M.S. , Topaz S.R. , Jones D.N. , Kolff W.J.
Published: March 2018

A Stepper Motor Driven Reciprocating Pump (SDRP) can replace roller pumps and rotary pumps for cardio pulmonary bypass, hemodialysis and regional perfusion. The blood pumping ventricles are basically the same as ventricles used for air driven artificial hearts and ventricular assist devices. The electric stepper motor uses a flexible linkage belt to produce a reciprocating movement, which pushes a hard sphere into the diaphragm of the blood ventricles. The SDRP generates pulsatile flow and has a small priming volume. The preset power level of the motor driver limits the maximum potential outflow pressure, so the driver acts as a safety device. A double pump can be made by connecting two fluid pumping chambers to opposing sides of the motor base. Each pump generates pulsatile flow. Pressure and flow studies with water were undertaken. Preliminary blood studies showed low hemolysis, even when circulating a small amount of blood up to 16 hours.
Implantable insulin pumps: diagnosis and management of decreased flow rates using radionuclide investigation
Authors: Boulahdour H. , Behar A. , Haardt M.-J. , Selam J-L.
Published: March 2018

The aim of this study was to develop a diagnostic procedure for pumping unit malfunction by radionuclide imaging (RI) and to validate the method by comparing the results with those obtained using more conventional methods. Fifteen radionuclide investigations were performed in 11 patients with intraperitoneal implantable insulin pumps. One mCi of 99 mTc in 1 ml isotonic sodium chloride was injected into the reservoir. The results based on catheter visualization and peritoneal accumulation were compared blindly to the efficacy of alkaline rinses and laparoscopic findings. In all RI stoppage cases except one alkaline rinses failed to restore flow. Where laparoscopy was performed, comparisons were concordant i.e. no outflow from the tip of the catheter. The RI images obtained were reproduced in vitro using a pump under normal flow conditions and complete proximal and distal catheter obstruction. RI is a safe, quick non invasive method which allows the location of the site of pump/catheter malfunction within a one step procedure and the prediction of the efficacy of sodium hydroxide rinses.