bluuebunny/crossref_metadata_2025 huggingface dataset:
Double Pass Dialysis: A New Method of Renal Replacement in Patients with Malfunctioning Vascular Access
Authors: Brendolan A. , Ronco C. , Crepaldi C. , Bragantini L. , Milan M. , Gastaldon F. , La Greca G.
Published: March 2018

Several patients undergoing chronic renal replacement therapy present problems related to their vascular access. Low blood flows and high rates of recirculation are common in such patients in which, for this reason, it becomes difficult to apply highly efficient techniques or techniques where diffusion and convection are combined as in hemodiafiltration. In these patients we studied the possibility of partially recirculating the blood in the extracorporeal circuit in order to increase the flow rate per single hollow fiber; we defined our system “double pass dialysis”. We evaluated the system's efficiency in 12 patients during 24 dialysis sessions: 12 high flux dialysis sessions (without reinfusion) and 12 hemodiafiltration sessions (9 liters reinfusion). Different surfaces of polyacrylonitrile dialyzers were utilized (1.3-1.7-2.1 sqm) at 250 and 350 ml/min of blood flow with or without 100 ml/min of recirculation. During each dialysis session blood and dialysate samples were taken in order to calculate BUN, Creatinine, Phosphate and Inuline clearances from both the blood and dialysate side. The clearances of low molecular weight solutes were not really influenced by the artificial increase of the blood flow, but on the other hand, the clearances of higher molecular weight solutes increased from 10 to 30% during both high flux dialysis and hemodiafiltration with recirculation. This increase was evident mostly in hemodiafiltration suggesting that the cleaning effect on the membrane has a positive impact on the permeability. The good clinical results obtained with the double pass dialysis show that the system is safe and reliable and may become a valid support in critical situations in order to reach adequate dialysis treatment.
Continuous ambulatory peritoneal dialysis using self-made, ultrafiltration-sterilized, L-lactate-based dialysis solution
Authors: Ing T.S. , Yu A.W. , Agrawal B. , Tiwari P.K. , McShane A.P. , Kuna P.P. , Gandhi V.C.
Published: March 2018

Continuous ambulatory peritoneal dialysis was successfully carried out in 6 end-stage renal failure patients using self-made, ultrafiltration-sterilized dialysis solutions. A Y-set was used to deliver the above solutions to sterile plastic bags.
Individual differences in biocompatibility responses to hemodialysis
Authors: Skroeder N.R. , Kjellstrand P. , Holmquist B. , Kjellstrand C.M. , Jacobson S.H.
Published: March 2018

There are very few reports in the literature on individual differences in the response to dialysis treatment. We studied the influence of the individual patient, dialysis membrane quality, blood-flow (Qb) and surface area on leukocyte activation and complement generation (C3a) during 234 hemodialysis treatments using Cuprophan (CU), hemophane (HE) and polyamide (PA) dialyzers. The most common reaction was a decrease in leukocyte count and an increase in C3a after 15 minutes of treatment. Leukocyte overshoot by the end of dialysis was observed at high Qb for all three membranes but at low Qb only during CU treatments. The reaction patterns were influenced by the quality of the membrane, area and Qb. Analysis of each individual patient showed for a large number of treatments reaction patterns corresponding to those described in the literature. However, some patients reacted differently. In four patients (20%), the nadir in leukocyte count and maximum in C3a concentration was reached considerably later during CU-dialysis. Three patients were devoid of pronounced early leukocyte response but presented with the late overshoot during CU-dialysis. Three other patients reacted with an early drop in leukocyte count and a rapid increase in C3a generation during PA treatments but not during HE treatments. Three other patients reacted vice versa. A particular mode of dialysis treatment may thus be biocompatible for some patients but not necessarily for all. In the case biocompatibility is desired the individual response to the particular dialysis mode needs to be identified. The underlying mechanisms warrant further studies.
Comparison of approximate and iterative methods to calculate the efficiency of haemodialysis as KT/V
Authors: Smye S.W. , Lewis D. , Will E. , Bartlett C.
Published: March 2018

Dialysis dose is given by the index KT/V, where K is the dialyser urea clearance, T the duration of dialysis and V the notional urea distribution volume. KT/V may be calculated using the single pool model and an iterative calculation which requires a computer program. Three estimates of KT/V, each based on simple correction of the log ratio in (C0/C1), where C0, C1 denote the pre- and post-dialysis blood urea concentrations in mg/ml, were developed and compared with the values of KT/V given by iteration. The first estimate was given by adding two terms to the log ratio to account for the effect of ultrafiltration and urea generation while the second and third estimates were given by increasing the log ratio by 12.5% and 15% respectively. All estimates gave good agreement when compared with the iterative technique by Bland-Altman analysis for 27 patients on standard 4 hour dialysis treatment using 4 different dialysers (0.71<KT/V<1.62). The mean difference in all cases was less than 0.025 and the differences were not clinically significant. The use of these approximate formulae to estimate dialysis efficiency avoids the need for complex calculation or additional blood samples.
Behavior of Beta 2-microglobulin (B2-m) serum levels in uremic patients
Authors: Mioli V.A. , Balestra E. , Bibiano L. , Dellabella S. , Fanciulli E. , Gaffi G. , Perilli A. , Petroselli F. , Ricciatti A.M. , Carletti P.
Published: March 2018

This Study Was Performed In 97 Hemodialysis Patients (85 On Hd And 12 On Capd) To Investigate The Possible Correlation Between B2-M And Hemodialysis-Related Amyloidosis Syndromes (Hra-S); Differences In B2-M And Hra Behavior Between Patients Hemodialysed With Cellulose And Synthetic Membranes Were Also Included In The Present Study. Data Indicate That B2-M Levels Are Not Correlated With Dialysis Length Or With The Type Of Membrane Used For The Dialysis. On The Contrary, In 16 Patients With The Carpal Tunnel Syndrome, A Significant Correlation Was Found Between The Cts, The Dialysis Length And The Type Of Membrane (Greater Incidence With Cellulosic Membranes).
Changes in molecular pattern of atrial natriuretic peptide in hemodialysis patients
Authors: Akiba T. , Ando K. , Marumo F.
Published: March 2018

An attempt was made to clarify whether the molecular forms of atrial natriuretic peptide (ANP) in the plasma of stable hemodialysis patients differ from those of healthy volunteers, and whether the ANP molecular forms in plasma might change during hemodialysis treatment. Ten stable hemodialysis patients with no clinical signs of cardiac disease were treated for 4 hours by a hollow fiber-type dialyzer. Plasma ANP concentrations before dialysis were 210 ± 101.6 pg/ml (mean ± SD), which were significantly higher than that of volunteers (59.2 ± 37.2 pg/ml, n=25). They were significantly decreased to 71.6 ± 60.1 pg/ml after dialysis. Molecular patterns of ANP were measured by gel permeation chromatography and reverse-phase high performance liquid chromatography. Immunoreactive alpha-ANP peaks of GPC, which co-migrated with authentic alpha-, beta-, and gamma-ANP, were supposed to be alpha-, beta-, and gamma-ANP. The plasma of four patients contained a beta-ANP peak before dialysis, and three of the four still contained a beta-ANP peak after dialysis. These results showed that the middle-molecular-weight ANP, which co-migrated with authetic beta-ANP and is supposed to be beta-ANP, may particularly be secreted in clinically stable hemodialysis patients.
An animal model for the evaluation of graft thrombosis in the acute phase on carbon-lined PTFE prosthesis
Authors: Babatasi G. , Bara L , Galateau F. , Agostini D. , Massetti M. , Gerard J.L. , Rossi A. , Bloch M.F. , Samama M.M. , Khayat A.
Published: March 2018

Fortyfive carbon-lined (CL) and 45 standard (ST) 4 mm internal diameter polytetra-fluoroethylene (PTFE) grafts were implanted as aortic interposition in 90 rabbits. A pilot study of 20 animals: 10 CL and 10 ST grafts were used to develop microsurgical techniques, then 60 grafts were placed in 60 New Zealand rabbits with lower morbidity. The two hours graft patency (Doppler and angiographic studies) showed better patency rate in CL group (93% versus 80%). In 10 animals, platelet accumulation was investigated in vivo using gammacamera imaging after injection of autologous platelets labeled with Indium111. In vitro, radioactivity counting of the explanted midgraft sections at 2 hours revealed 6 times greater activity in ST grafts (6.60 ± 1.98 x 103platelets/mm2 versus 0.82 ± 0.25 x 103 platelets/mm2; p<0.05). Light microscopy found platelet and fibrin deposition (PFD) in nearly all ST grafts whereas PFD were found in only 13% of the CL grafts corresponding to those thrombosed (chi2: 61.117, p<0.001). Carbon-lining decreases platelet accumulation on PTFE grafts in the acute phase of a new experimental model.
Ex vivo Design Evaluation of an Implantable Blood Port System
Authors: Hoekstra A. , Elstrodt J.M.
Published: March 2018

A prototype of a totally implantable vascular catheter-port system was evaluated on its design using three animals of different species. The catheter was placed either intravenously or intra-arterially, and connected to the port which was retained outside the body. Parameters used for design evaluation or functionality testing were focused on the use and handling of the port-catheter system such as easiness of flushing, injection, blood sampling, septum stiffness to prevent blood reflux after pushing the septum, and possible diffusion of blood into the saline present in the port-catheter system. This pilot experiment showed that the septum of the prototype port system was too flexible, and that the distance between septum and base of the port was too short. These findings have led to a major improvement of the catheter-port system, currently successfully used in cancer chemotherapy.
Influence of Warm Ischemia on Isolation and Primary Culture of Hepatocytes from Rat Liver for a Hybrid Artificial Liver
Authors: Kon H. , Matsushita M. , Takahashi M. , Nishikawa M. , Taguchi K. , Koike M. , Kamachi H. , Uchino J.
Published: March 2018

To assess the possibility of using hepatocytes from ischemic liver, as a bioreactor of a hybrid artificial liver, we investigated the influence of warm ischemia on the isolation and culture of hepatocytes in rats. Warm ischemia was induced by clamping the liver hilus and the animals were divided into 3 groups according to the duration of ischemia: group A (no ischemia), group B (10 minutes) and group C (20 minutes). Hepatocytes were isolated by the collagenase perfusion method and cultured for 5 days. The yield and viability of the isolated hepatocytes were lower in group C. Rate of attachment was decreased as the duration of ischemia increased. There was no significant difference observed in functions in culture. Sufficient hepatocytes, as a bioreactor, can be isolated and cultured from warm ischemic liver within 10 minutes. Though the number of available hepatocytes were diminished, hepatocytes procured from longer warm ischemic liver could be utilized as a bioreactor.
Preparation and Storage in Plasma-Lyte a of Platelets Collected with the Cell Separator CS3000 plus Equipped with the PLT30-Separation and TNX6 Collection Chambers
Authors: Valbonesi M. , Florio G. , Frisoni R. , Morelli F.
Published: March 2018

The last five years have been characterized by the presentation of new cell separators the main task of which is the collection of high yield-high quality platelets. The CS3000 is an old apparatus which has undergone rejuvenation to sustain the assault of its new competitors. The CS3000 Plus Omnix system is the latest version to be offered along wth a combination of TNX-6 separation/PLT30 collection chambers for optimal platelet collection. In this paper we present our results with this apparatus and configuration after its adaptation to the collection and storage of platelets in a non-plasma medium, the Baxter Plasma-Lyte A. After separation the platelet product (PC) was left in the collection chamber and resuspended with 200 ml of Plasma-Lyte A instead of being resuspended in autologous plasma as usual. Plasma was collected in a separate bag (400–450 ml) for transfusion or fractionation purposes. PC quality was assessed by evaluating the platelet yield (4.17 ± 1.8 x 1011), and the WBC contamination (4.8 ± 2.6 x 105). The presence of platelet aggregates (platelet count after aggregate fixation with formalin/platelet count after disaggregation in EDTA), the aggregation induced by ADP, collagen and ristocetin, the hypotonic shock response and the stability of membrane glycoproteins (CD 62 - 63 - 36 - 42b - 51) were measured in the preapheresis samples and in the PC immediately after, 24 and 72 hours after collection. These results were totally satisfactory as was the post-transfusion survival measured as corrected count increment in 10 transfusions to non refractory patients. It is concluded that the preparation and storage in Plasma-Lyte A of platelets collected with the CS3000 Plus-Omnix apparatus, with the TNX6-PLT30 configuration is not only feasible but advisable.
De Novo Membranous Glomerulopathy in Renal Allografts with Unusual Histology
Authors: Lal S.M. , Luger A.M. , Saha L.K. , Ross G.
Published: March 2018

We describe two cases of de novo membranous glomerulopathy in the renal allograft, with unusual histologic findings. In one patient the allograft nephrectomy specimen showed numerous foam cells in the intima of hyperplastic arteries along with prominent features of chronic rejection. In the other patient, prominent IgM deposits were seen in the glomerular mesangium without chronic rejection.
Evaluation of new small barium alginate microcapsules
Authors: Cappai A. , Petruzzo P. , Ruiu G. , Congiu T. , Dessy E. , De Seta W. , Santa Cruz G. , Brotzu G.
Published: March 2018

Microencapsulation of islets of Langerhans has been proposed in order to prevent immune rejection and possible recurrence of autoimmune disease. This study introduces a fast simple one-step microencapsulation procedure which allows the production of small sized barium-alginate beads. The volume of the microcapsules produced was approximately that of the encapsulated islets. Consequently, the insulin kinetics and the oxygen diffusion were favoured, while the transplanted tissue volume was reduced. Electron microscopy and immunoisolating testing were performed to evaluate the molecular cut-off, the physical and chemical characteristics of these microcapsules. Immunohistochemical staining and perifusion experiments of microencapsulated pancreatic islets showed their viability after the encapsulation procedure as well as in vivo experiments. In fact, microencapsulated porcine islets were implanted intraperitoneally into streptozotocindiabetic rats. The xenografts reversed the hyperglycemic state and functioned for a period ranging from 9 to 385 days. The low mannuronic acid concentration and the purity grade of the alginate, exerted a combined influence on the capsule biocompatibility as in vivo studies showed
Treatment of Homozygous and Double Heterozygous Familial Hypercholesterolemia Children with LDL-Apheresis
Authors: Stefanutti C. , Vivenzio A. , Colombo C. , Di Giacomo S. , Mazzarella B. , Berni A. , Nigri A. , Koga N.
Published: March 2018

Within the framework of a seven-year clinical experience on treatment of severe hyperlipoproteinemia with/without associated coronary heart disease, with therapeutic plasmapheresis (APO B-100-containing lipoprotein-apheresis), we focused the present report on two young patients aged 7 and 11 years, respectively. The older patient is a boy treated since 1990 by plasma-exchange, cascade filtration-low density lipoprotein apheresis (LDL-apheresis), and dextrane sulphate-LDL apheresis. Over the treatment period the patient was submitted to three consecutive coronary angiographies. The second patient is a girl first submitted to a coronary angiography and then treated with dextrane sulphate-LDL apheresis. Up to now, a total of one-hundred therapeutic plasmaphereses have been performed. The interval of treatment was of fifteen days, and a volume of 2-3000 ml of plasma was processed at each session. The systems used were the following: DIDECO Vivacell BT 798-A, DIDECO Vivacell BT 798-A + BT 803, DIDECO BT 985 (Dideco, Mirandola, Italy), KANEKA MA-01 (Kanegafuchi, Osaka, Japan). Mean (SD) plasma apo B-100-containing major lipoprotein-LDL, Lp(a) - levels during treatment, are reported below:

LDL-Apheresis

mg/dl    LDL-Chol    Lp(a)

before    479 (83)    58 (15)

after    103 (67)    21 (14)

The treatment was very well tolerated. Rare, moderate hypotensive events occurred. Nevertheless, all procedures were regularly completed. A mild hypochromic anemia, regressed using drug treatment, was observed in the boy. Along with the improvement of plasma atherogenic profile, a regression of skin xanthomas and unchanged favourable coronary angiograms, were obtained in the above mentioned patient.
Urea, Creatinine and Phosphate Kinetic Modeling during Dialysis: Application to Pediatric Hemodialysis
Authors: Maasrani M. , Jaffrin M.Y. , Fischbach M. , Boudailliez B.
Published: March 2018

The kinetics of urea, creatinine and phosphate removal during dialysis were investigated in pediatric patients using a two-pool model taking into account fluid shifts and mass transfer between the two compartments. It is found that even urea must be described by a two-pool model since it presents a post dialysis rebound due to equilibration between the two compartments. Phosphate plasma concentration drops very sharply during the first hour of dialysis and rises rapidly during the rebound period. This pattern cannot be accounted for by the classical two-pool model with constant generation rate and mass transfer coefficients, but corresponds to a large time-dependent phosphate influx from the intracellular compartment in which phosphate is generated by biochemical reactions or liberated from the bones. This influx was calculated for four patients representing 8 dialysis sessions and was found to reach a plateau after 90 minutes of dialysis, dropping rapidly during the rebound period.
Elastomeric Valves, a New Design
Authors: Hulsbergen M.H. , Topaz S. , Kumar A. , Bishop N.D. , Shelton A. , Granger S. , Chiang B.Y. , DE Boer L. , Luikenaar R.A. , Mohammed S.F. , Kolff W.J.
Published: March 2018

The convex bileaflet valve replaces the flat biflap inflow valve designed by Long Sheng Yu and the tricusp semilunair outflow valve. One reason is easier manufacturing. Convex bileaflet valves are developed for the 11, 20, 40, 70 and 140cc ventricles. Testing included curves (Cardiac Output versus Venous Pressure, Cardiac Output versus Heart rate), flow visualization studies, paint and bloodbag studies. The curves and flow visualization were done by connecting ventricles to one of our standard mock circulations. Paint and bloodbag studies were done by connecting the hearts to a bloodbag, but the bag was filled with water for the paint studies. The curves show high cardiac output, even with pumping at high heart rates (150 BPM+). The flow visualization shows a good stream through the sinus Valsalvae. No stagnating flow is visible. The bloodbag studies which provoke thrombosis show it on the edges of the heart valves, and little in the groove between the valve and the sinus Valsalvae. Heparninzation prevents the thrombosis. Results of our tests were good. The convex bileaflet valve seems to have good future.
Serious Renal Disease in Egypt
Authors: Essamie M.A. , Soliman A. , Fayad T.M.S. , Barsoum S. , Kjellstrand C.M.
Published: March 2018

We studied serious renal disease in Egypt by registering all 155 patients coming to the nephrology service at the University of Cairo during a period of 62 days in 1993. The patients presented with severe uremic symptoms. Admission creatinine and urea levels were high, 804 μmol/l and 64 mmol/l. Fifteen percent of the patients died; 115 underwent dialysis. Sixty patients presented with chronic renal failure; 53 with acute renal failure, but 24 of these were later found to have end-stage renal failure. Of 29 patients with true acute renal failure, 11 (38%) had pre-renal failure and 7 (24%) postrenal failure. Twenty-one patients were followed up after transplantation and chronic dialysis, another 17 had nephrotic syndrome, 3 hypertension, and one had asymptomatic urinary abnormalities. The most common specific etiology for chronic end-stage renal failure was diabetes mellitus type II in the older patients; second most common was Schistosoma in the younger ones. Most diabetic patients came from the city. All but one Schistosoma patient came from rural Egypt. In the 22 patients who underwent renal biopsy the most common diagnosis was mesangio capillary glomerulonephritis. The prevalence of acute renal failure, particularly iatrogenic-toxic, is increasing
In Vivo Comparative Study of Two Lactobionate Based Solutions for Prolonged Heart Preservation
Authors: Baufreton C. , Charloux C. , Jaffres P. , Paul M. , Roudot-Thoraval F. , Perennec J. , Astier A. , Loisance D.Y.
Published: March 2018

The duration of safe heart preservation must be improved. Using a heterotopic heart transplantation model, we compared in vivo the recovery of rabbits hearts preserved with a K+ Lactobionate based fluid (UW: University of Wisconsin solution) or with a Na+Lactobionate based fluid. In the “preservation” group, hearts were cold stored (4°C) for 6 hours with UW (n=9) or Na+Lactobionate solution (n=9). In the “transplantation” group, cold storage was followed by 3 hours of reperfusion (UW: n=8, Na+Lactobionate solution: n=7). Functional recovery, adenine nucleotide pool, circulating blood cardiac enzymes, circulating blood and tissue malondialdehyde (MDA) were measured. Left ventricular enddiastolic and developed pressures at different preload levels were better after preservation with UW than with Na+Lactobionate solution (p<0.05). Also with UW, adenosine diphosphate and total adenine nucleotide content were significantly higher than with Na+Lactobionate solution (p<0.05) whereas adenosine triphosphate, monophosphate and energy charges were similar. Cardiac enzymes and tissue MDA were similar with UW and Na+Lactobionate solution. In circulating blood, MDA was not detected. These results enhance the superiority of UW solution over a Na+Lactobionate based solution for long term heart preservation.
Hydraulic Refinement of An Intraarterial Microaxial Blood Pump
Authors: Sieβ T. , Reul H. , Rau G.
Published: March 2018

Intravascularly operating microaxial pumps have been introduced clinically proving to be useful tools for cardiac assist (1–4). However, a number of complications have been reported in literature associated with the extra-corporeal motor and the flexible drive shaft cable (5,6). In this paper, a new pump concept is presented which has been mechanically and hydraulically refined during the developing process. The drive shaft cable has been replaced by a proximally integrated micro electric motor and an extra-corporeal power supply (7). The conduit between pump and power supply consists of only an electrical power cable within the catheter resulting in a device which is indifferent to kinking and small curvature radii. Anticipated insertion difficulties, as a result of a large outer pump diameter, led to a two-step approach with an initial 6,4mm pump version and a secondary 5,4mm version. Both pumps meet the hydraulic requirement of at least 2.5I/min at a differential pressure of 80–100mmHg. The hydraulic refinements necessary to achieve the anticipated goal are based on ongoing hydrodynamic studies of the flow inside the pumps. Flow visualization on a 10:1 scale model as well as on 1:1 scale pumps have yielded significant improvements in the overall hydraulic performance of the pumps. One example of this iterative developing process by means of geometrical changes on the basis of flow visualization is illustrated for the 6.4mm pump.
Blood Platelet Activation and Membrane Glycoprotein Changes during Extracorporeal Life Support (Ecls). In Vitro Studies
Authors: Mellgren K. , Friberg L.G. , Hedner T. , Mellgren G. , Wadenvik H.
Published: March 2018

The aim of this study was to evaluate an in vitro model for investigation of platelet function parameters in an extracorporeal system. Two different perfusion pumps were compared, a roller pump (Polystan) and a centrifugal pump (Biomedicus). A continuous increase in glycoprotein (GP)1b-negative platelets was observed in both circuits. A marked increase of plasma β-thromboglobulin thromboglobulin concentration and a decrease of the intracellular pool of serotonin was observed, indicating a marked release of alpha as well as of dense granules. The plasma concentration of glycocalicin increased in parallel with a reduced platelet surface expression of GP1b, suggesting that the loss of GP1b is caused by proteolysis rather than by a downregulation of this receptor protein. It is concluded that ECLS results in a pronounced platelet degranulation and causes changes of important membrane receptors which might explain some of the bleeding problems observed in patients treated with ECLS. No significant difference was noted between the roller pump and the centrifugal pump. Trial of strategies, e.g. protease inhibitors and nitric oxide to revert this untoward effect of ECLS are highly warranted.
Multicentre Trial of a Programmable Implantable Insulin Pump in Type I Diabetes
Authors:   The Point Study II Group*, Pinget M. , Jeandidier N. , Ortega F. , Wix D. , Margetaux J. , Feinböck C. , Diglas J. , Mendl H. , Irsigler K. , Scavini M. , Petrella G. , Torri M. , Cristallo M. , Pozza G. , LÜddeke H.-J. , Groth T. , Renner R. , Hepp K.-D. , Selam J.-L. , Haardt M.-J. , Bethoux J.-P. , Dorange C. , Slama G. , Vague P. , Lassman-Vague V. , Belicar P. , Johansson M. , Hammarberg B. , Fahlström U. , Baselius L , Sjöholm G.
Published: March 2018

Programmable implantable pumps permitting variable-rate intraperitoneal insulin infusion are currently investigated as a potential alternative to subcutaneous insulin therapy. An improved version of the Siemens implantable system has been evaluated in 6 European centres on 31 type I diabetic patients treated for 10–30 months. Contrary to other pump models there were no proven pump malfunctions and only one no-flow reduction unrelated to catheter obstruction. The latter resulted in 12 surgical catheter replacements. There were 2.0 incidents of programmer malfunctions per patient-year easily managed by reconfiguration or replacement. Insulin remained clear and active in the pump reservoir and glycaemic control remained in the near-normoglycaemic range. Thus, insulin therapy with the Siemens implantable pump is feasible and effective up to 2.5 years.
Scanning Electron Microscopic Investigations of Surface Treated Large-Bore Catheters Used for Extracorporeal Detoxification Methods
Authors: Bambauer R. , Schiel R. , Mestres P. , Sioshansi P.
Published: March 2018

Typical complications caused by surface properties of synthetic catheter implants are infection, thrombosis, and stenosis. New methods for surface modification with the aim of reducing such complications are ion beam-based technologies. In our study 109 large-bore catheters without (n = 42) and with treated surfaces with silver (n = 39) or silicone (n = 28) were inserted into the interna jugular and the subclavian veins and were used for extracorporeal detoxification methods. After removal, the catheters were investigated with scanning electron microscopy (SEM) and for bacterial colonization. In 42 large-bore catheters without surface treatment deposits of fibrin, protein and blood cells were seen on the inner and outer surface. Bacterial colonization was observed In 38.1%. In contrast, the catheters with treated outer surfaces showed a very low thrombogenecity and a low contamination rate of 8.9%. The ion beam-based technologies reduce the thrombogenicity and infection rates of the catheter surfaces. In comparison to catheters without treated surfaces, catheters with surface treatment are good alternatives in blood contacting applications ranging from hemodialysis to oncology
Monitoring of Fes-Induced Muscle Activity by Continuous Emg-Recording
Authors: Girsch W. , Bijak M , Heger G. , Koller R. , Lanmüller H. , Mayr W. , Thoma H. , Losert U.
Published: March 2018

Functional Electrical Stimulation (FES) requires information on the stimulated muscle for adjustment of the stimulation current, avoidance of muscle fatigue during the conditioning period and long term follow-up. Several applications of chronical FES are in clinical practice, but a system for direct registration of muscle activity under FES still does not exist. In six sheep the right Latissimus Dorsi Muscle (LDM) and Thoracodorsal Nerve were exposed. Stimulation electrodes were applied to each nerve and 3 EMG-applied sensing electrodes were placed into each LDM. The LDM tendon was connected to a force transducer. Burst stimulation was applied and the amplitude was increased from 0 to 4 mA in steps from burst to burst. EMG (M-wave) was amplified and recorded continuously via modified instrumentation amplifier, oscilloscope and tape recorder. Isometric muscle tension was recorded using force transducer, AID interface and PC. Continuous EMG-recording was performed in all cases. Simultaneous recording of muscle tension and EMG revealed a close correlation (lrl=0.95, p < 0.0001) between muscle strength and amplitude of the M-wave. Continuous recording of the EMG seems to be a reliable method for direct monitoring of the stimulated muscle. Three intramuscular electrodes can provide enough information to monitor FES induced muscle activity.
Metabolic Response of Blood Cells to Synthetic Graft-Materials with Special Reference to a Fluoromer Passivated Dacron® Graft. An in Vitro Study Using Microcalorimetry
Authors: Swartbol P. , Pärsson H. , Nässberger L. , Norgren L.
Published: March 2018

Microcalorimetry was used to study in vitro the metabolic response from human platelets and leukocytes when incubated with three different synthetic graft-materials. The graft to be studied primarily was Fluoromer Passivated Dacron (FPD) which was compared with ePTFE and with a knitted Teflon graft. A rapid increase in the metabolic activity of platelets was observed, followed by a steady-state for more than one hour, while the platelet metabolism did not differ among the various graft-materials. Leukocytes incubated with FPD showed a high initial metabolism, with a peak after about 15 minutes. After 60 minutes the metabolic response had reached control values. ePTFE and Teflon grafts differed significantly from FPD, without causing any peak metabolic activity. It may be concluded that FPD and ePTFE grafts, as evaluated in vitro, activate platelets to the same extent, while FPD causes a more extensive leukocyte activation. Whether these findings can be interpreted as differences in thrombogenicity and inflammatory responses has not been proven, but seems probable. This in vitro method should make it possible to further study human responses to synthetic materials a method possibly more reliable than animal experiments.
Ventricular flow Dynamic past Bileaflet Prosthetic Heart Valves
Authors: Garitey V. , Gandelheid T. , Fuseri J. , PÉlissier R. , Rieu R.
Published: March 2018

To characterise hydrodynamic properties of prosthetic heart valves in mitral position, ultrasonic velocity measurements were performed using a cardiovascular simulator. A Duromedics and a Saint-Jude Medical bileaflet heart valve were tested. The Saint-Jude valve was oriented first in an anatomical position, i.e. the tilt axis parallel to the septal wall, and then in an anti-anatomical position. In the anti-anatomical position, from mid diastole to mid systole, two contrarotative vortices are generated in the ventricle by the interaction between the flow directed by the leaflets downstream from the lateral orifices and the ventricular wall motions. In the anatomical position, the mitral flow penetrates the ventricle principally through the lateral orifice proximal to the septal wall, due to the vortex in the atrial chamber. The mitral inflow then circulates along the septal wall to the apex, and produces a large ventricular vortex during systole. In the anatomical position, the Saint-Jude thus provides a better ventricular washout during this phase. The mitral inflow through the Duromedics in the anti-anatomical position produces two contrarotative vortices in the ventricle, but in the opposite sense than downstream the Saint-Jude valve; the flows that penetrate through the lateral orifices are directed to the ventricular walls and then recirculate to the centre of the ventricle, providing a very fluctuating flow near the apex. Thus, a slight difference in valve design produces a significant difference in the ventricular flow fields.
Hemoscan™: A Dialysis Machine-Integrated Blood Volume Monitor
Authors: Paolini F. , Mancini E. , Bosetto A. , Santoro A.
Published: March 2018

We describe an opto-electronic device capable of measuring the hemoglobin concentration (Hgb) non-invasively and continuously, hence the percentage changes in blood volume (BV) during dialysis treatment by means of the optical absorption of monochromatic light by the blood in the arterial line. This method has been validated during several in vitro and in vivo tests, during which the system has shown a low sensitivity to all the common intra-dialytic interference factors, such as oxygen saturation (max. err.=1.6%), blood flow (max. err. =1.8%), osmotic pressure (max. err.=0.7°) and hydraulic pressure (max. err.=0.6°), a high precision (std. err.≤0.1 g/dl) and a good accordance (Hgb mean err.=0.1 g/dl; std. err.=0.38 g/dl; BV mean err.=0.1%; std. err.=1.6%) with the corresponding values derived from standard laboratory tests.
High-Frequency Oscillatory Ventilation and Nitric Oxide: Alternative or Complementary to ECMO
Authors: Kachel W. , Varnholt V. , Lasch P. , Müller W , Lorenz C. , Wirth H.
Published: March 2018

One hundred and seventy-seven term or near-term neonates were referred to an ECMO center for severe PPHN-associated diseases. In 2 time periods from 1987 to 1991 and from 1992 to April 1995 alternative treatment modes were tried in an attempt to obviate ECMO. During the first time period patients underwent trial high-frequency oscillatory ventilation before ECMO. In the second time period patients first received inhaled NO followed by HFOV in a non-responders. If this also failed HFOV was combined with I NO. In both time periods about 40% of the patients were spared ECMO treatment by these alternative treatment modalities. I NO only benefited 15% of the ECMO candidates who apparently had fared just as well on HFOV alone in the preceding time period. While patients who were improved by I NO were spared HFOV with its potential severe complications, i.e. air leaks and cardiocirculatory instability, more extended long-term studies will have to show which of these 2 treatment modalities (INO or HFOV) should be given first priority in an attempt to avoid ECMO in neonates with severe respiratory failure.
Bioelectrical Impedance Analysis: Clinical Tool in Assessing Total Body Water and Thoracic Fluid
Authors: De Vries P.M.J.M. , Noordegraaf A. Vonk , Van Der Meer B.J.M. , Woltjer H.H. , De Vries J.P.P.M.
Published: March 2018

Bioelectrical impedance analysis forms a non-invasive tool for detection of body fluids. Total body measurement gives total body water (TBW) and, in case of multi-frequency analysis, of intra- and extracellular fluid volume. The thoracic approach measures thoracic fluid (TF). The set-up of both techniques is discussed. An overview is given of the clinical usefulness of the total body technique to monitor fluid changes and the process of refill during hemodialysis and to detect dry weight. The simultaneous measurement of TBW and TF was applied to obtain a more detailed picture of the body fluids. In a group of healty subjects the age dependency of both variables was shown. During hemodialyss TBW and TF showed a major and comparable decrease. Fluid retention during cardiac surgery led to a slightly more pronounced increase of TF than of TBW. The combination of both impedance techniques offers clinicians a means to monitor alterations in fluid status in patients in more detail.
Assessment of the Best Compatible Dialysis System: Feasible Application for Bioelectrical Impedance
Authors: Bazzato G. , Scanferla F.
Published: March 2018

Since the introduction of hemodialysis procedure several attempts have been made to elucidate the material tissue interaction in order to evaluate the behaviour of immunosystem cellular and humoral responses to the material of patients on renal replacement therapy. Biochemical and sierological parameters have been considered as method for assessment of the best compatible dialysis. Nevertheless blood tests don't probably reflect the most important symptoms of clinical relevance. Thus we have applied bioelectrical impedance to assess the whole procedure/patient system. Resistance (R) changes during hemodialysis resulted strictly inversely correlated to the body weight variations during HD session (R < 0.96). Reactance (Xc) has also shown a progressive increase associated with an increment of phase angle, while Xc during clinical events such as hypotension, vomiting or cramps showed some transient falls. Also nutritional status and clinical well-being manifested a close relationship with bioelectrical parameters. It is therefore our feeling that BIA monitoring will provide a feasible tool to assess dialysis adequacy, of which biocompatibility represent a crucial aspect.
Acid-Base Balance Determination on Ultrafiltrate in Two-Chamber Technique Hemodiafiltration (PFD)
Authors: Ghezzi P. M. , Guarnieri A. , Tetta C.
Published: March 2018

Correction of the acid-base balance in uremic patients during hemodiafiltration (HFD) may be biased by an inadequate monitoring of phi and blood gases. HDF performed with the two-chamber technique (PFD) generates pure ultrafiltrate (uf) unmixed with dialysate. We carried out 84 determinations of HCO−3 levels in 15 different PFD patients by measuring the pH and pCO2 of the uf, then correlated the values with those simultaneously evaluated on arterial blood with standard methods. The mean HCO−3 levels (mmol/L) were 23.21±2.49 in blood samples and 25.54±3.07 in uf, with a mean difference of -2.33±1.46. Statistical analysis gave: t=13.5 (p=O) (one-sample analysis), r=0.86 (p=0) (linear regression analysis) and a good agreement between the two clinical measurements (81 out of 84 data points fell within the 95% confidence interval) (Bland-Altman analysis). In conclusion, we suggest that during HDF performed with the two-chamber technique, the patient's HCO−3 level can be monitored on the uf without blood sampling.
Hemodialysis using a Constant Potassium Gradient: Rationale of a Multicenter Study
Authors: Redaelli B. , Limido D. , Beretta P. , Viganò M.R.
Published: March 2018

The aim of this study is to evaluate the relationship between two different procedures for potassium removal during hemodialysis (HD) and cardiac arrhythmias. Cell excitability and the transmission of impulses may be influenced by variations of resting membrane potential (RMP). The rapid decrease of plasma potassium during the first two hours of standard HD causes a membrane hyperpolarization. A different K+ kinetic, with a gradual and constant elimination of K+ during HD, may reduce this further unphysiological aspect and its clinical consequences. This can be obtained keeping blood-dialysate K+ gradient as constant as possible with the use of a dialysate K+ concentration (Kd) decreasing during HD. Our experimental studies on various K+ intradialytic gradients seem to indicate as optimal to this purpose K+ gradients of 1.5 mEq/l at the beginning of dialysis, esponentially decreasing during treatment to Kd values of 2.5 mEq/l at the end of dialysis (variable Kd). Patients included in the trial will be submitted to two different methods of treatment with Kd 2 mEq/l and variable Kd, and to a 24 hours ECG the day of dialysis. We will compare the number of intra and interdialytic premature ventricular complexes to evaluate the impact of two different models of potassium removal on arrhythmias.
Elevated Plasma Lipoprotein(a) Levels and Hypoalbuminemia in Peritoneal Dialysis Patients
Authors: Ross E.A. , Shah G.M. , Kashyap M.L.
Published: March 2018

Plasma lipoprotein(a), Lp(a), is strongly and independently associated with atherosclerosis, and levels are elevated in hemodialysis (HD) patients and in some studies of those on peritoneal dialysis (PD). We hypothesized that protein losses and hypoalbuminemia could stimulate hepatic Lp(a) synthesis, and this effect would be accentuated in PD patients with malnutrition. The PD subjects (n=24) had higher plasma Lp(a) levels than those (n=10) on HD (median 34.4 vs 21.0 mg/dl, p<0.05), and values exceed normal in 62.5% vs 20% of the subjects (p<0.03), respectively. The serum albumin levels inversely correlated with concentrations of Lp(a) and apolipoprotein B, as well as the apolipoprotein B/AI ratio. In conclusion, plasma Lp(a) concentrations are frequently elevated in PD as well as HD patients. Measuring Lp(a) levels is useful in identifying patients at increased atherogenic risk, which may not be reflected in routine lipid profiles. The negative correlation between plasma Lp(a) and albumin levels suggests that the latter may be linked pathophysiologically to hepatic Lp(a) production. The association of hypoalbuminemia with higher Lp(a) values is of particular concern because malnutrition frequently occurs in PD patients.
Characterization of the Resistance of Pyrolytic Carbon to Abrasive Wear
Authors: Vitale E. , Giusti P.
Published: March 2018

Si-alloyed pyrolitic carbon (PyC) is currently employed in many biomedical devices, due to its fairly good biological compatibility and non biodegradeability. For prosthetic heart valve applications, required to operate safely for many years, the resistance to abrasive wear is one of the limiting factors which must be accurately evaluated. The present study reports on abrasive wear testing of Ti/PyC and PyC/PyC sliding couples. For both couples it was found that the wear behaviour can be shifted from a low wear regime, characterised by very small wear rates and reduced scatter, to a high wear regime, characterised by high wear rates and high scatter, due to the presence of particle contamination coming from the environment and/or from the specimen polishing process. Actual biomedical devices, particularly heart valves, should not experience the high wear regime, due to the absence of any hard particle contamination source. The wear observed in these items is in fact minimal and may depend on mechanisms other than abrasive wear. In these conditions the experimental evaluation of the wear behaviour should definetely be performed by tests on actual devices.
Change in Hemorrheological and Biochemical Parameters following Membrane Differential Filtration
Authors: Brunner R. , Widder R.A. , Walter P. , Borberg H. , Oette K.
Published: March 2018

Introduction: The elimination of high molecular weight proteins may have a positive influence on disorders of the microcirculation due to an improvement in rheological parameters. We therefore attempted to evaluate the rheological efficacy of membrane differential filtration (MDF). Patients and methods: Ten patients suffering from macular disease underwent MDF. Rheological and biochemical parameters as well as visual acuity were determined one day before and after therapy: The study aimed at a reduction in plasma viscosity, standardized whole blood viscosity at hematocrit 0.45 and erythrocyte aggregation at hematocrit 0.3. Results: Severe side-effects were not observed. The rheological parameters were significantly reduced. In detail the posttreatment values were reduced as compared to the pretreatment values as follows: plasma viscosity 85%, standardised whole blood viscosity 86% (hematocrit 0.45), erythrocyte aggregation 59% (hematocrit 0.3), total protein 81%, IgG 66%, IgA 59%, IgM 33%, alpha-2-macroglobulin 30%, triglycerides 102%, total cholesterol 47%, VLDL cholesterol 94%, LDL cholesterol 33%, HDL cholesterol 62%. Visual acuity was improved in 7/10 patients. Conclusions: MDF is a safe and highly effective method for lowering biochemical and improving rheological parameters which led to improvement in visual acuity. We have already replaced plasma exchange with MDF in our clinical practice of hemorrheological therapy.
Cell Sources for Bioartificial Liver Support
Authors: Stange J. , Mitzner S.
Published: March 2018

The present review discusses hepatocyte sources for a bioartificial liver. Intended requirements for cell sources are for example: synthesis of plasma proteins, detoxification and regulation. The need for highly differentiated hepatocytes is stressed. Furthermore, the gap between this objective on the one hand and the real possibilities as they appear today on the other is shown. Alternatives to primarily isolated hepatocytes are discussed, thereby elucidating the limits of established cell lines. In summary, it is postulated that the results expected from a bioartificial liver, are closely related to the source and type of cells used.
Isolation of Porcine Hepatocytes from Slaughterhouse Organs
Authors: Koebe H.G. , Schildberg F.W.
Published: March 2018

Recent developments in the field of hybrid artificial liver research have increased the demand for an unlimited supply of primary hepatocytes. At present, liver cells are mainly isolated from anesthetized pigs, since slaughterhouse organs have been regarded as a cell-source of minor quality. A modified enzymatic isolation technique for the successful harvesting of viable porcine liver cells from slaughterhouse organs is introduced. Digestion of the left medial liver lobe (n=114) resulted in 1.2 ± 0.35 x 10E7 viable hepatocytes per gram tissue and an overall yield of 2.23 ± 0.48 x 10E9 cells per isolation (viability: 94 ± 2.4%). Morphological integrity of hepatocytes in long-term immobilization culture systems was assessed by electron microscopic follow-up. Stable DNA-contents (52±2 μg) and low alanine-amino-transferase (ALAT) release were measured after early culture adaptation. Urea production under NH4CI, Albumin secretion, total bile acid synthesis (3.5 pmol/hr/μg DNA) and 7-ethoxicoumarin o-deethylase (ECOD) activity demonstrated functional activity and maintenance of Type IA1 cytochrome P450 (CYP450) dependent metabolism in cultured hepatocytes for at least 10 days. Compared to ex vivo isolation results in the literature, we could not see any disadvantages in the use of liver cells from slaughterhouse organs, but would like to point out four advantages. It saves animal lives, labor, costs, and time. Research groups especially with no animal housing and/ or surgical facilities should evaluate the presented technique for their own needs to make use of this unlimited cell source.