bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of Discontinuous Flow Centrifugation Compared with Cascade Filtration in Waldenstrom's Macroglobulinemia: A Pilot Study
Authors: Valbonesi M. , Montani F. , Guzzini F. , Angelini G. , Florio G.
Published: March 2018

In the treatment of Waldenstrom's macroglobulinemia (WM) and lipoprotein or immune complex mediated diseases, centrifugal and membrane plasma separation systems have been successfully employed over the past years. More recently, semiselective double filtration systems have been used in isolated cases. While it is hoped that cascade filtration (CF) will soon become a routine technique, a note of caution came from some investigators because of the lack of any evidence that CF does really deplete patients' plasma of known pathogenic macromolecules.

The aim of this study was to test the efficacy of CF in the removal of IgM paraproteins in comparison with discontinuous flow centrifugation (DFC).

Eight patients were treated by DFC and seven by CF; there were no significant differences between the two groups in terms of sex, age, clinical severity and IgM plasma concentration. After DFC or CF sessions, IgM concentration diminished by 50% and plasma viscosity by 60%, producing a comparable mean reduction in patients' clinical severity. Our in vivo results thus preliminarily answer the question whether CF is capable of removing known pathogenic macromolecules from patiets' plasma, and the technique appears to warrant further investigations.
Polymer Resins with Amino Acid Containing Pendants for Sorption of Bilirubin. II. Polyamide Resins with Various Basic Amino Acids
Authors: Henning D.S. , Brown G.R. , St-Pierre L.E.
Published: March 2018

Short peptides, three to eight amino acids in length, containing various combinations of alanine, arginine, lysine, histidine and tyrosine have been synthesized onto water-swellable polyamide resin by the solid phase peptide synthesis method. The amount of bilirubin adsorbed from aqueous buffer solution (pH = 7.8) by the resins increases with increasing basicity of the amino acids in the pendant. As the number of basic amino acids on the pendant is increased fron one to five a 4.7 fold enhancement in the adsorption capacity is seen for arginine while a 9.3 fold enhancement is obtained for lysine. A corresponding increase in length for the non-basic histidine results in a 6 fold enhancement. With alanine the adsorption capacity is uneffected by an increase in pendant length.
Hematological and Biochemical Studies in Calves Living over 100 Days with the Polymethylmethacrylate Total Artificial Heart TNS Brno II
Authors: Dostál M. , Vašků J. , Černý J. , Šotolová O. , Guba P. , Vašků Jan , Urbánek P. , Pavlíček V. , Vašků A. , Nečas J. , Sládek T. , Trbušek V. , Bednařík B.
Published: March 2018

A polymethylmethacrylate total artificial heart (kinetic components made of polyetherurethane) of TNS Brno II type was implanted into seven calves (2-5 months of age) surviving for the average of 152.4 ± 19.1 days after the implantation. During the entire post-operative period the animals received oral warfarin-sodium, acetylsalicylic acid, dipyridamole and alpha-tocopherol. Blood was taken for biochemical and hematological examinations twice a week from the jugular vein. During the experiments there were decreases in the number of red blood cells, hematocrit and hemoglobin levels. Plasma free hemoglobin and serum enzymes (alkaline phosphatase, AST, ALT, LDH) increased. Coagulation tests were abnormal because anticoagulation therapy was used. There were minimal changes in the number of white blood cells and platelets, fibrinogen, blood pH, blood glucose, serum electrolytes, bilirubin (total and direct), creatinine, blood urea, and lactate. Possible reasons for observed changes include the gradual rise in the central venous pressure and damaged function of the liver parenchyma. Other factors playing a possible role in inducing changes in laboratory findings are also discussed.
Rat Microsomes and Cytosol Immobilized by Microencapsulation in Artificial Cells
Authors: Yuan Z.Y. , Chang T.M.S.
Published: March 2018

Rat liver microsomes and cytosol have been co-immobilized by microencapsulation into artificial cells. The immobilized enzyme retained good enzyme activity. Enzyme kinetics, storage stability, pH profiles and temperature profiles have been analyzed.
Comparative Analysis of Two Volumetrical Ultrafiltration Monitors for Hemodialysis
Authors: Berden J.H.M. , Wokke J.M.P. , Koene R.A.P.
Published: March 2018

Controlled ultrafiltration (UF) during hemodialysis may prevent dialysis associated hypotension. A prerequisite for controlled ultrafiltration is an accurate measurement of ultrafiltration. Volumetric measurement is the best currently available method for this purpose. In this study we compared in a clinical setting two volumetric ultrafiltration monitors (UFM): one device constructed in our hospital using oval flowmeters (UFM-N) and the other using electromagnetic flow transducers (UFM-G: UFM 10-2, Gambro Lund Sweden).

The UF measurements of both UFM's were compared with UF calculated from bedscales weight monitoring and standard scales determinations. During dual needle hemodialysis (n = 8) with a hollow fiber dialyzer the accuracy of the UFM-N was 91% and that of the UFM-G 97%. During dual needle dialysis with a parallel flow dialyzer the UFM-N appeared to be more sensitive for pulsatile changes in the dialysate flow due to the greater compliance of this type of dialyzer. The accuracy of the UFM-N in this setting was 80%, while that of the UFM-G was 87% (n = 11). During single needle dialysis with a parallel flow dialyzer (n = 14) only the UFM-G was tested and it measured UF with an accuracy of 92%. Finally the UFM-G can control UF actively by adjusting the TMP to obtain a given UF rate. The accuracy of the UFM-G in this setting was 94%, and the lineair regression correlation coefficient between planned UF and actually obtained UF was 0.974 (n - 61).

In conclusion volumetric monitoring of UF is accurate and reliable, but its accuracy is dependent on the type of dialyzer used. The UFM-G proved to be useful in every dialysis modality tested, while the UFM-N can be used in dual-needle dialysis using hollow fiber dialyzers.
Plasma Exchange in Severe Erythema Nodosum Leprosum
Authors: Wallach D. , Bussel A. , Koch P. , Pennec J. , Cottenot F.
Published: March 2018

Four patients with severe erythema nodosum leprosum were treated by plasma exchange and/or fresh frozen plasma infusions after failure of classical therapy.

After the procedures, the patients improved rapidly; with a follow-up between 4 and 7 years after the last plasma exchange, no clinical relapse was noted. The replacement fluids were variable; the most beneficial procedure seemed to be plasma exchange replaced with fresh frozen plasma.

Elimination of circulating immune complexes, replacement of a lacking plasma factor are possible mechanisms of action. Plasma exchange may also work like a regulator of immune mechanisms, since it has been shown that there is a depression of suppressor cells in erythema nodosum leprosum.
Preparation of Small Volume, Leuko and Erythrocyte Very Poor Platelet Concentrates
Authors: Valbonesi M. , Angelini G. , Malfanti L. , Lercari G. , Fella M. , Calderisi S. , Anselmo A. , Balistreri M.
Published: March 2018

Recently developed automated discontinuous flow centrifuge (DFC) separators can produce leuko- and erythrocyte-poor platelet concentrates (PC). According to general experience with these machines it is difficult to obtain more than 4 × 1011 platelets, though a second program set up by Coffe et al. appears to produce PC containing approximately 5 × 1011 platelets suspended in a plasma volume of 390 ml. At our center we employed a new Dideco cell separator equipped with the surge pump and a technique developed for the production of small volume, RBC and WBC-very poor PC. In 60 routine procedures we obtained the following results: mean processing time 87 ±11 minutes; final volume of PC 136 ± 19 ml, with a mean platelet yield of 5.21 × 1011 platelets. WBC contamination was 1.8 × 108 (93% lymphocytes) and RBC were 3.1 × 108. Plasma volume as well as WBC and RBC contamination were reduced by recirculating PC after the 6th pass.

The demand for single donor platelet concentrates (PC) is increasing progressively. Recently developed automated cell separators can produce leukocyte (WBC) and erythrocyte (RBC) poor PC. With these machines it may be difficult to obtain PC containing at least 4 × 1011 platelets and less than 1 × 109 leukocytes (1, 2, 3) since donor variables such as hematocrit, precounts, buffy coat formation and initial plasma light transmission are of paramount importance for the efficiency of the program (3). At our center a prototype discontinuous flow centrifuge (DFC) cell separator equipped with the surge pump was studied (4). It produced PC containing 3.58 ±1.5 × 1011 platelets suspended in a mean of 346.32 ± 51.7 ml of plasma and contaminated by 0.63 ± 0.51 × 109 WBC (95% lymphocytes). The quality of the PC was satisfactory, with good maintenance of platelet functions as measured by ristocetin-induced aggregation and malonaldehyde production, but our study brought to light the main limitations of the system, namely the variability of WBC and RBC contamination and the excessive loss of plasma.

In this study we report on a technique developed with the Unicell prototype to produce small volume, WBC and RBC-very poor PC.
Mineral Metabolism during a Hemofiltration Session in Children
Authors: Bianchi M. L. , Bettinelli A. , Soldati L. , Saccaggi A. , Ortolani S. , Edefonti A.
Published: March 2018

We studied the effects of one session of hemofiltration on the mineral metabolism in a group of uremic children. We observed an increase of calcemia, accompained by positive calcium balance, and a decrease of plasma phosphate and PTH-MM. No substantial loss of plasma 25-OH D was found. It is concluded that hemofiltration has a positive effect on calcemia and is very effective in removing phosphate, but it acts only temporarily on PTH removal.

An adequate calcium concentration must be provided in the substitution fluid.
Hemoperfusion Based on Artificial Cells for Aluminium and Iron Removal, Immunosorption, Fulminant Hepatic Failure, Uremia, Poisoning and Metabolic Assists
Authors: Chang T.M.S.
Published: March 2018

The author reviewed artificial cells and their applications in hemoperfusion for chronic renal failure, poisoning, fulminant hepatic failure, removal of aluminium and iron, and metabolic assists. Other areas reviewed included artificial cells containing enzymes, multienzymes, immunosorbents, cell cultures and other areas.

Artificial cells can be formed as membrane coated adsorbent or microencapsulated adsorbent, enzymes and cells (1-3). The large surface to volume relationship and the ultrathin membrane of artificial cells allows the rapid equilibration of metabolites (1-3). Artificial cells containing enzymes, ion exchange resin and activated charcoal have been used for hemoperfusion (4). The microencapsulated or membrane coated absorbents, enzymes, cells, immunosorbents and other material are prevented from releasing unwanted material into the circulation and prevented from adverse effects on blood cells. Because of the problem of charcoal in releasing emboli and depleting platelets (5) we first developed coated activated charcoal hemoperfusion for clinical application (6, 7). This has been used extensively in clinical studies. The artificial cell approach has also been applied to a number of other hemoperfusion approaches. The lack of space only allows this paper to summarize some of the approaches originated from this research centre.
Routine Clinical Applications of Hemodialysis-Hemoperfusion in Chronic Renal Failure: Case Reports
Authors: Barré P.E. , Gonda A. , Chang T.M.S.
Published: March 2018

Five hemodialysis patients were treated with combined hemodialysis-hemoperfusion with their conventional hemodialyzer plus a 70-gram ultrathin collodion coated activated charcoal device for a total of 63 months. Indications for this therapy included pericarditis, peripheral neuropathy, clotting of conventional hemodialyzers and reduction of dialysis time and frequency. The outcome was beneficial in all cases and stable biochemical and hematological parameters were maintained. No increase in heparin requirements was noted and the therapy was thought to be cost-effective.
Resin Hemoperfusion for Drug Intoxication - An Update
Authors: Raja R.M.
Published: March 2018

Hemoperfusion through Amberlite XAD-4 resin column has been shown to effectively remove sedative-hypnotics, analgesics and other drugs causing acute intoxication. There is no appreciable clinical toxicity and dramatic shortening of coma time and possible decrease in mortality may be achieved. Thrombocytopenia and clotting may be diminished by pre-perfusion coating with 2.5% albumin. Albumin coating may facilitate the repeated use of hemoperfusion without any complications. More recently, resin hemoperfusion has been used for procainamide, N-acetylprocainamide and theophylline intoxication achieving exceptionally high clearance rates.
Removal of Denatured Proteins with Artificial Reticuloendothelial System (ARES)
Authors: Maeda K. , Tsuruta Y. , Shinzato T. , Yamada K.
Published: March 2018

Basic research has revealed that hydrophobic residues increased on the molecular surface of the denatured IgG and that the denatured proteins in the plasma can be removed by several sorbents of different amino acids bonded from polyvinylalcohol hydroxide residue with a covalent bond. Thus, an artificial reticulo-endothelial system was developed to supplement the human reticulo-endothelial system (RES) by removing denatured proteins from the patient's plasma. Clinically, angiitis and Raynaud's phenomenon associated with collagen disease such as systemic lupus erythematosus were remarkably reduced following a series of ARES treatments. The proteins adsorbed on the ARES were analyzed by two-dimensional electrophoresis. Virtually no albumin was detected, and IgG (constant isoelectric point), IgM, IgA, IgA dimer, C3, G4, fibrinogen and other unidentified spots were found in the elute from the ARES column.
Adsorption of Lipoprotein Containing Apolipoprotein-B through Plasma Separation for Treatment of Familial Hypercholesterolemia
Authors: Odaka M. , Kobayashi H. , Soeda K. , Murotani N. , Saito Y. , Nishide T. , Yoshida S. , Tani N. , Takata S.
Published: March 2018

For the treatment of familial hypercholesterolemia, Liposorber LA-40 was clinically applied. The Liposorber is a commercially developed affinity adsorbent for plasma perfusion which selectivily adsorbs low density lipoproteins and very low density lipoproteins and is specially designed for plasmapheretic treatment of hypercholesterolemia.

The Liposorber column, containing activated cellulose beads having an affinity for liporpotein containing apolipoprotein-B, has an excellent adsorption capacity, excellent selectivity, minimum albumin loss. This new apheresis system was applied to 2 clinical cases.

After seven months of trial perfusion every 2 weeks, patient condition was good, with a level of total cholesterol under 300 mg/dl. No replacement fluids were given during or after treatment.

In this paper, clinical results of these patients were shown and the mechanism of adsorption of this specific adsorbent was discussed.
Selective Removal of Pathogenetic Macromolecules Directly from Whole Blood by Double Filtration Technique
Authors: Agishi T.
Published: March 2018

Double filtration plasmapheresis (DFPP) is a technique devised in an attempt to selectively remove pathogenetic macromolecules such as antibodies, immune complexes or viscosity-increasing substances directly from blood. In order to realize the differential filtration principle, two filters, one for separation of plasma and another for fractionation of plasma components, are installed in an extracorporeal circulation line. Selective separation of the plasma components is dependent on the filtration property of the two filters. Clinical experiences evidence the usefulness of this technique in regard to conservation of human blood products for supplementation.
The Influence of Peritoneal Dialysis on the Outcome of Transplantation
Authors: Diaz-Buxo J.A. , Walker P.J. , Burgess W.P. , Farmer C.D. , Chandler J.T. , Faircloth W. , Callahan M. , Holt K.L.
Published: March 2018

The Authors' series of 44 patients transplanted after peritoneal dialysis suggests that the results of renal transplantation are comparable to those on hemodialysis.
Development and Clinical Application of Perfluorochemical Artificial Blood
Authors: Ohyanagi H. , Saitoh Y.
Published: March 2018

A review of the authors' experience on the use of Fluosol DA. This includes studies on animals and also clinical trials on patients.
Renal Hemodynamic Changes after β-Blocker-Diuretic Combination Therapy in Azotemic Hypertensive Patients
Authors: Zawada E.T.
Published: March 2018

The effects of β-blocker therapy with either nadolol or propranolol were compared during therapy with hydrochlorothiazide (HCTZ) 50 mg b.i.d. on glomerular filtration rate (GFR), effective renal plasma flow (ERPF), effective renal blood flow (ERBF), blood pressure, and heart rate in 22 patients with essential hypertension and mild to moderate renal insufficiency. The clearances of inulin and para-aminohippurate (PAH) were used to estimate renal hemodynamic measurements. These parameters were determined after 2 weeks of HCTZ plus placebo and at 1, 3, and 6 months after the addition of β-blocker to HCTZ. Significant reductions in blood pressure and heart rate were seen, but no significant reduction of renal hemodynamics were seen with either β-blocker-HCTZ combination. Since 50% of the patients in each drug group were either Black or White, hemodynamic data were also analyzed by race. One month after β-blocker addition there was a slight reduction of GFR in both Whites (47 ± 6 vs. 40 ± 5 ml/min, p > .05) and Blacks (44 ± 5 vs. 40 ± 6 ml/min, p < .05). By month 6, GFR in Whites rose to 57 ± 9 ml/min, whereas in Blacks it fell significantly to 36 ± 6 ml/min (p < .01). Similarly, at month 1, ERBF declined by 12% and 13% in Whites and Blacks, respectively. However, at month 6, ERBF rose by 28% in Whites and remained 11% lower in Blacks, p< .05. In summary, in the group as a whole neither β-blocker significantly altered renal hemodynamics when added to HCTZ therapy. However, after six months of combined therapy, Whites had elevations whereas Blacks had reductions of GFR and ERBF. These results suggest that the addition of β-blocker to diuretic therapy may be detrimental to certain hypertensive patients with limited renal reserve accelerating their need for a renal replacement therapy.
Peritoneal Sclerosis in Continuous Ambulatory Peritoneal Dialysis Patients Dialyzed Exclusively with Lactate-Buffered Dialysate
Authors: Daugirdas J.T. , Gandhi V.C. , McShane A.P. , Leehey D.J. , Chan A.Y. , Jablokow V.R. , Ing T.S.
Published: March 2018

Peritoneal sclerosis occurred in two patients treated by continuous ambulatory peritoneal dialysis (CAPD) using only lactate-buffered dialysate. Both patients had recurrent peritonitis and the second patient had multiple, minor abdominal operations. Patients receiving lactate-buffered CAPD are not immune from peritoneal sclerosis. Recurrent peritonitis and repeated abdominal surgery might be important causative factors.
Transmembrane pressures generated by filtrate line suction maneuvers and predilution fluid replacement during in vitro continuous arteriovenous hemofiltration
Authors: Golper T.A. , Kaplan A.A. , Narasimhan N. , Leone M.
Published: March 2018

A recirculating in vitro CAVH system was designed which generated pulsatile blood and filtrate flows. Monitors recorded hydrostatic pressures simultaneously in the arterial, venous and filtrate lines during varying plasma or blood flow rates and predilution (vs postdilution) replacement fluid flow rates. Similar hydrostatic pressure monitoring was carried out during multiple maneuvers to generate suction on the filtrate side of the hemofilter (Amicon® D-20's and Renaflo®‘s).

With a plasma flow (Qp) of 100 cc/min and predilution replacement fluid infusion rate of 500 cc/hr, the arterial pressure was 5% greater than during postdilution (p < 0.05). With a blood flow (Qb) of 50 cc/min, predilution fluid replacement rates of 500 and 1000 cc/hr, and vacuum suction applied to the filtrate compartment, the arterial pressure was 33% lower than during postdilution fluid replacement (p < 0.03). Nonetheless, the ultrafiltration rate (UFR) was 10 to 30% higher (p < 0.03). At many other combinations of Qp, Qb and replacement rates and modes, there were no significant changes in arterial pressure.

Despite these arterial pressure changes, > 70% of the transmembrane hydrostatic pressure (TMP) was due to the negative pressure induced by filtrate suction (gravity, Gomco®, wall suction, IMED®). The actual pressure in the filtrate compartment measured during Gomco® or wall suction was 3/4 of that stated by their gauges, presumably due to leakage. Maximum wall suction never generated TMP's > 150 mmHg. Using an IMED® 960 as the suction device (bypassing the air alarm), for a Qp of 50, IMED® settings of 300, 600 and 900 cc/hr generated TMP's of 67 ± 3, 77 ± 3, and 97 ± 3 mmHg, respectively. When Qp was 20 cc/min, an IMED® setting of 999 cc/hr generated TMP's consistently < 136 mmHg but UFR was only 668 ± 246 cc/hr. With the IMED® set at 999 cc/hr and Qp of 30 cc/min, the TMP was < 132 mmHg and the UFR was 944 ± 10 cc/hr. No filters ruptured.

These suction maneuvers do not generate enough pressure to rupture filters. When Qp is low the IMED® may not generate the UFR one expects. Predilution will probably alleviate this concern.
A new technique for hemodilution, preparation of autologous platelet-rich plasma and intraoperative blood salvage in cardiac surgery
Authors: Ferrari M. , Zia S. , Valbonesi M. , Henriquet F. , Venere G. , Spagnolo S. , Grasso M.A. , Panzani I.
Published: March 2018

We have developed a new system for the production of autologous platelet-rich plasma and red blood cell concentrates to be used in autologous transfusion support of cardiac surgery patients. In 15 operations no homologous blood products were required. Costs were diminished since with the same harness it was possible to carry out the intraoperative blood salvage and concentrate the erythrocytes contained in the oxygenator and its lines. Indirect costs were also reduced since no infective complication was observed due to homologous blood products.
“Are the Differences between ‘High Performance’ Pacing Leads Clinically Significant? A Comparison of Sintered Platinum and Activated Carbon”
Authors: Bourke J.P. , Jameson S. , Howell L. , Gold R.G.
Published: March 2018

A retrospective assessment was performed of the acute implantation characteristics of two pacing leads, one with a sintered platinum (S 80-T) electrode and the other with an activated vitreous carbon (412-S) electrode in 124 patients. The S80-T lead had a significantly lower implantation threshold. The differences between the two leads in sensing properties, in current flow at threshold voltage and at the output of the generator were not significant at implantation. The 412-S lead had a higher impedance measurement than the S-80-T at implantation but this was mainly due to the resistance differences of the conductors rather than to electrode-patient interactions.

A subgroup of 20 patients had chronic threshold measurements. The S 80-T lead had a significantly lower chronic voltage threshold.

However because the acute and chronic differences are small we conclude that, although these differences are statistically significant, they are not clinically significant.

Both can justifiably be termed ‘high-performance’ leads.
Hypertension Profiling by Total Body Water (Tbw) Determinations in Patients on Chronic Hemodialysis
Authors: Thylén P. , Ericsson F. , Odar-Cederlöf I. , Kjellstrand C.M.
Published: March 2018

Hypertension is an important risk factor in hemodialysis patients. Fluid overload and increased peripheral resistance are considered the two main causes. We studied the relation between volume state and blood pressure in 18 hemodialysis patients. Actual total body water (aTBW) was measured as tritium space and “ideal” total body water (iTBW) by an anthropometric method. The difference between aTBW and iTBW was considered a measure of fluid excess or deficit.

Twelve patients were overhydrated, 5%-23%. Their predialysis blood pressure was significantly correlated to their degree of fluid excess; systolic BP:r=0.71, p=0.03, diastolic BP:r=0.73, p=0.02, mean arterial BP:r=0.76, p=0.03. Five of these patients had multiple antihypertensive drugs instead of adequate ultrafiltration. Five patients had a fluid deficit of -3 to -13% and hypertension due to vasoconstriction. Four of these were adequately treated with antihypertensive drugs but had exaggerated ultrafiltration. TBW determination with tritium is simple to perform and gives information on the volume state and thereby on the cause of hypertension in hemodialysis patients. Based on this, appropriate treatment can be chosen.
In Vivo Solute Elimination of Paired Filtration Dialysis
Authors: Vanholder R. , De Smet R. , Gervasio R. , Ringoir S.
Published: March 2018

Paired filtration dialysis (PFD) is a new dialysis strategy whereby a hemofilter and a hemodialyzer are coupled in series. It has been assumed that this approach allows a better solute elimination than conventional hemodialysis (HD), allowing a shortening of dialysis time. To evaluate this hypothesis, solute elimination with PFD either with 0.4 m2 polysulphone (PS) and 1.36 m2 cuprophan (CU) 3×3 h/wk, or with 0.4 m2 PS and 1.06 m2 CU 3×4 h/wk, was compared to HD with 1.36 m2 CU, 3×4 hours weekly in the same patients. During PFD, 10L were ultrafiltered and substituted by saline. Overall extraction of UV absorbing solutes (MW < 10,000 Dalton), and extraction of individual solutes identified by high performance liquid chromatography (HPLC) were compared as well as urea kinetics. For PFD 3×3 h overall extraction of UV-absorbing compounds and of hippuric acid was significantly higher than for HD 3×4 h (p < 0.05). Overall extraction of UV-absorbing copounds and of all but one individual compound under study was markedly higher for PFD 3×4 h vs conventional HD 3×4 h (p < 0.01), in spite of a higher diffusive area with the latter technique. No differences in urea kinetics were observed for the 3 strategies. It is concluded that solute extraction during PFD is higher than during HD, if the treatment time is the same. Even if treatment is shortened to 3×3 h weekly, solute extraction with PFD is at least as efficient as with HD.
Hemoglobin-Based Artificial Blood: New Polymeric Derivatives of Hemoglobin with Low Oxygen Affinity
Authors: Dellacherie E. , Vigneron C.
Published: March 2018

To make stroma-free hemoglobin (SFHb) capable of carrying oxygen satisfactorily in vivo it is necessary both to improve its intravascular persistence and to reduce its affinity for oxygen. The method used up to now has consisted of chemical modification of SFHb to lower its oxygen affinity (fixation of permanent effector inside the phosphate binding site or intramolecular crosslinking of the deoxy form of SFHb), then polymerization or substitution with polymers. We have designed new functionalized polymers (from dextran and polyoxyethylene), capable of mimicking the effect of the natural intraerythrocyte effector, 2,3-disphosphoglycerate, i.e. of decreasing its affinity for oxygen, and we have linked these polymers chemically to oxyHb. All the resulting conjugates have lower oxygen affinity than SFHb and, when injected into rats, do not lead to hemoglobinuria. Preliminary in vivo tests also showed that these conjugates possess no acute toxicity. Further experiments with rats are now under way (60% and 80% hemorrhagic shocks) with the aim of evaluating whether these new products can be regarded as potential candidates for blood substitution.
Effect of Magnetic Fluids on the Efficiency of an Electromagnetic Actuator Prototype
Authors: Ferrari G. , De Lazzari C. , Mimmo R. , Tosti G. , Ambrosi D.
Published: March 2018

An electromagnetic actuator to substitute ventricular function presents some advantages compared with different energy converters. The drastic reduction of the moving parts leads to greater reliability and an accurate control system can be set up. Its major limitations concern weight, heat dissipation and, finally, the overall pump efficiency which is usually rather low. We investigated the possibility of using magnetic fluids in an electromagnetic actuator. Limitations intrinsic to the magnetic fluids prevent their being used as pumping elements but they can be useful to increase the pump efficiency by reducing losses in the magnetic circuit. A remarkable increase in pump efficiency was attained. It is necessary to point out that in designing the electromagnetic actuator the focus was on the pump efficiency with and without the magnetic fluids more than on its performance.
Removal of Endotoxin and Cytokines by Adsorbents and the Effect of Plasma Protein Binding
Authors: Nagaki M. , Hughes R.D. , Lau J.Y.N. , Williams Roger
Published: March 2018

High serum levels of endotoxin and cytokines, through which its activity is mediated, have been shown to be associated with disease severity in septic shock and in fulminant hepatic failure. In the present study, we have investigated the ability of activated charcoals (DHP-1 and Adsorba 150C) and uncharged resin (Amberlite XAD-7) to adsorb lipopolysaccharide (LPS) and various cytokines, namely tumour necrosis factor (TNF), interleukin-1 (IL-1), interleukin-6 (IL-6), interferon-α (IFN-α) and interferon-γ (IFN-γ). The capacities of the adsorbents were assessed by measurement of their equilibrium adsorption isotherms for these substances labelled with 125I. There was no single adsorbent that uniformly adsorbed LPS and the cytokines from phosphate buffered saline or human plasma. DHP-1 charcoal was superior to Adsorba 150C for all substances and was the most effective adsorbent for binding LPS, IL-1α and IFN-γ. Amberlite XAD-7 resin was most effective for TNF, IL-6 and IFN-α, but bound little LPS, particularly from human plasma. Ultrafiltration through a membrane which retains substances of molecular weight > 50 kD did not filter the cytokines from human plasma, although the molecular weight of the cytokines range from 17 to 22 kD. This demonstrated that TNF, IL-1, IL-6, IFN-α and IFN-γ readily bind to proteins and/or other large molecules in plasma.
Ten Years Experience with Plasma Exchange in Renal Transplantation
Authors: Frascà G.M. , Martella D. , Vangelista A. , Bonomini V.
Published: March 2018

Plasma exchange has been used in our renal transplantation programme for over ten years to treat 86 patients divided into four groups. Five patients had preformed cytotoxic antibodies before transplantation (group A); 13 sensitized patients (>60% PRA) underwent prophylactic plasma exchange in the immediate postoperative period (group B); 62 patients were treated for acute vascular rejection (group C); six patients had chronic graft rejection (group D). Plasma exchange is a valid tool for the treatment of acute vascular rejection, provided that it is started before irreversible graft damage occurs: 75% rejection crises were reversed by plasma exchange and the actuarial graft survival from the rejection episode was 75% at one year, 66% at two and 50% at five years. Serum creatinine before treatment and glomerular thrombosis at graft biopsy correlated with the response to plasma exchange. In sensitized patients and in those with chronic rejection the results were disappointing and suggest that in these clinical conditions plasma exchange should be used only in selected cases.
Measurement of Blood flow through Av-Fistulae by Means of Doppler Sonography in Regularly Haemodialysed Patients
Authors: Krpan D. , Demarin V. , Prot F. , Milutinovic S. , Molnar V. , Milutinovic E.
Published: March 2018

In regularly dialyzed patients a variety of pathological events can negatively influence haemodynamics and blood flow through arteriovenous fistula, leading to inadequate blood flow through the dialyzer or disturbances in hemodynamics of the whole body. It therefore appears important to quantify flow velocity and volume flow through the arteriovenous fistula in such cases. We used a Vasoview computer controlled system for noninvasive vascular diagnostics based on B-scan “real-time” ultrasound for imaging the structure of tissue, combined with pulsed Doppler ultrasound for determination of hemodynamics. Thirty patients (16 males and 14 females, aged 45 ± 10 years; range 23 to 61 years), with different periods spent on hemodialysis (5.5 ± 3.1 years, range 1 to 11 years) were included in this study. The average systolic, diastolic and mean blood volume flows were 2131.8 ± 565.8, 972.0 ± 309.6 and 728.4 ± 287.4 ml/min, respectively. The mean blood volume flow was calculated by integration of the area under curve of blood flow in one heart cycle on the Doppler signal. It is calculated by the apparatus and displayed on the screen during measurement. The average blood vessel diameter was 9.1 ± 1.3 mm (μ ± σ). The results revealed a marked inter-individual variation in volume flow through arteriovenous fistulae of dialyzed uremics (range 240.0 to 1200.0 ml/min). Doppler ultrasound thus appears to be a valuable method for determination of blood flow through arteriovenous fistula of dialyzed uremics as well as for detection of hemodynamics disturbances of interest, such as turbulent blood flow.
A New Method to Evaluate the Capd-Catheter-Exit and other Percutaneous Devices
Authors: Knabe C. , Große-Siestrup C. , Becker H. , Pustelnik A. , Gahl G.
Published: March 2018

A method that has proved to be the most sensitive approach for the early diagnosis of infection of the oral mucosa around dental implants has been used to monitor the exit-sites of percutaneous devices. For three months the state of the skin-catheter interface of 13 CAPD-patients was examined every four weeks. This examination included the measurement of pocket depth with the aid of a periodontal probe, the measurement of SFFR (sulcus-fluid-flow-rate) using standardized filter paper strips and a bacteriological swab of the exit-site. The results obtained demonstrated that SFFR can be measured around percutaneous implants. The measurement of SFFR appeared to be more useful in the monitoring of exit-sites of percutaneous devices than the measurement of pocket depth or the use of bacteriological swabs. Further studies for prolonged periods are necessary to determine whether measurement of SFFR can reliably predict onset of exit-site infection before clinical signs become evident
Serum Alpha-1 Acid Glycoprotein in Chronic Renal Failure and Hemodialysis
Authors: Vasson M-P. , Paul J-L. , Couderc R. , Albuisson E. , Bargnoux P-J. , Baguet J-C. , Raichvarg D.
Published: March 2018

The total concentration and concanavalin A (ConA)-dependent microheterogeneity of alpha-1 acid glycoprotein (AAG) were studied in thirty hemodialyzed uremic patients and eighteen non-dialyzed uremic patients, by comparison with healthy volunteers. Serum concentrations of AAG were significantly higher in the non-dialyzed uremic (1.27 ± 0.47 g/l) and hemodialyzed patients (1.29 ± 0.33 g/l) than in the volunteers (0.79 ± 0.09 g/l). The proportions of strongly ConA-reactive AAG fractions were also higher in non-dialyzed uremic (16.7%) and hemodialyzed patients (18.5%) than in volunteers (14.1%). These data may be related to an increase in bi-antennary glycans, as observed in patients on peritoneal dialysis, together with a probable change in sialylation. AAG serum levels and microheterogeneity were similar in non-dialyzed and hemodialyzed patients and did not appear in the dialyzed patients to depend on the type of dialysis membrane used, i.e. cuprophan (CU), cellulose acetate (CA), hemophan (HE), polyacrylonitrile (PAN), and polysulfon (PS), in spite of differences in biocompatibility. In patients dialyzed with CA membranes, there was a distinct decrease in the ConA non-reactive fraction (38.0%) and an increase in ConA slightly-reactive (42.2%) and strongly-reactive (19.7%) fractions. Differences in AAG serum levels and ConA reactivity between patients dialyzed with CA and PAN membranes seem to justify further investigations of other acute-phase reactants and immunological parameters.
Development of a Wearable Glucose Sensor; Studies in Healthy Volunteers and in Diabetic Patients
Authors: Aalders A.L. , Schmidt F.J. , Schoonen A.J.M. , Broek I.R. , Maessen A.G.F.M. , Doorenbos H.
Published: March 2018

A glucose sensor with a subcutaneous dialysis system was tested in six healthy volunteers during an oral glucose tolerance test and in ten diabetic patients with hyperglycemia during rapid decline of blood glucose levels. There was a good correlation between sensor and blood glucose values. During oral glucose tolerance tests in the volunteers, there was a mean delay of 4.4. minutes in the rise of the value registered subcutaneously and of 8.2 minutes in the fall of the curves. In the diabetic patients the maximum delay was 22 minutes. Nine days after insertion of the dialysis system it was still functioning well.
Studies on Contact Lens Materials
Authors: Alyanak H. , Aksoy S. , Hasirci N.
Published: March 2018

The development of plastics with the optical properties of glass led promptly to their use as contact lenses and intra-ocular lenses to rectify certain visual defects. Research to improve these polymeric materials is continuous but there is not much in the literature since most of the findings are patented.

In this work, polymethyl methacrylate, the most commonly used lens material was chosen as the base material and its co and terpolymers were prepared using 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidinone, hexamethyl disiloxane, and polypropylene glycol. The transparency, refractive index, contact angle, density, equilibrium water content, and percent hydration properties were examined. Theoretical values were calculated for linear expansion and oxygen permeation from the density and hydration values.
An in Vitro Technique to assess Oxygenator Potential for Respiratory Failure Therapies
Authors: Kawak A.M. , Gaylor J.D.S. , Simpson K. , Kirkland M.
Published: March 2018

To assess microporous membrane oxygenators (MMO) for long-term respiratory support, an in vitro test of 4 days duration has been developed. The objective is to screen oxygenators before they undergo expensive animal trials. As a sensitive indicator of performance change, CO2 transfer rates (VCO2) are determined with fresh bovine blood at the start, after 48 hours and after 96 hours of perfusion. Blood is used only for gas exchange evaluation and is replaced with plasma in the intervening periods. Data are obtained at blood flow rates (QB) of 1.0, 1.5 and 2.0 l/min for gas: blood flow ratios (QG:QB) of 2:1 and 5:1. The test has been conducted on Bentley BOS-CM50 oxygenators (n=10). With heated dry air ventilation there was no significnat change in VCO2 with time for all QB and QG:QB combinations. Plasma leakage did not occur into the gas compartment of the MMO. Similar results were obtained with heated humidified air ventilation. The findings are in agreement with existing animal studies of 4-7 days duration.
Encapsulated Hepatocytes for Controlling Hyperbilirubinemia in Gunn Rats
Authors: Bruni S. , Chang T.M.S.
Published: March 2018

Hepatocytes encapsulated in an alginate-polylysine-membrane were used to lower bilirubin levels in hyperbilirubinemia. The animal model was the Gunn rat. The microencapsulated hepatocytes were implanted intraperitoneally. 15×166 microencapsulated hepatocytes from Wistar rats lowered the bilirubin from 14 mg/100 ml to 6 mg/100 ml after 20 days. 15×106 microencapsulated hepatocytes from Sprague-Dawley rats lowered the bilirubin levels from 8 mg/100 ml to 5 mg/100 ml. They were as effective as free Sprague-Dawley hepatocytes. 12×106 Guinea pig hepatocytes, whether encapsulated or free, lowered the bilirubin from 9.36 mg/100ml to 4.37 mg/100 ml.
Patient and Technique Survival for Blind and Sighted Diabetics on Continuous Ambulatory Peritoneal Dialysis: A Ten-Year Analysis
Authors: Chandran P.K.G. , Lane T. , Flynn C.T.
Published: March 2018

A retrospective analysis of patient and technique survival over 10 years in a group of 66 diabetics (40 being blind) and 71 nondiabetics was undertaken. Patient survival profiles showed that the blind diabetics lived longer than the sighted, but for a shorter time than the nondiabetics. In technique success, the sighted diabetics outdid the blind and the nondiabetics, long term. Short term, the blind performed better than sighted diabetics. The key to success and longer survival on CAPD depended on motivation on the part of the patient, patient's acceptance of given disability, family (social) support, and willingness on the part of renal care personnel to train the disabled diabetic to perform CAPD. With adequate education and support, blind diabetics did CAPD as well as sighted patients. There was no increased frequency of peritonitis in blind diabetics compared to sighted diabetics. Both blind diabetics and nondiabetics had fewer episodes than sighted diabetics. Intraperitoneal route of insulin administration achieved good glycemic control in diabetic population. Refractory congestive cardiac failure and/or fatal arrhythmias was the most common cardiac cause of death in diabetics on CAPD.
Timing for Implantation and Transplantation in Mechanical Bridge to Transplantation
Authors: Moritz A. , Rokitansky A. , Trubel W. , Laufer G. , Schima H. , Prodinger A. , Laczkovics A. , Wolner E.
Published: March 2018

The implantation of a mechanical blood pump in a deteriorating candidate for heart transplantation is indicated in general if the cardiac index is less than 1.9 L/min/m2 despite maximal inotropic support. Deterioration of end organ function may be taken as a second factor indicating the need for mechanical support as patients with acute onset of shock may react differently from patients with chronic deterioration. Preoperative need for dialysis largely reduces the chances of long-term survival. The time on support should be long enough to normalize or at least improve secondarily damaged organ systems, but with time infectious and thromboembolic complications will increase. So optimal periods for artificial heart support range between two days and four weeks. Age less than 40 years is a positive predictor for outcome in TAH bridging. The general guidelines, however, do not preclude a favourable outcome in complicated cases, as we show in our own series.
Patient Selection for Mechanical Circulatory Support as a Bridge to Cardiac Transplantation
Authors: Friedel N. , Viazis P. , Schießler A. , Warnecke H. , Hennig E. , Hetzer R.
Published: March 2018

Between 7/87 and 9/90 thirty-four patients underwent total artificial heart (Berlin Heart) (n=2) or biventricular assist device (Berlin Heart) (n=32) implantation as a bridge to cardiac transplantation. The time of mechanical support ranged from 2 to 60 days, for a mean of 19.2 days. Twenty-three patients received heart transplants, with 74% 30-day survival and 52% long-term survival. Implantation of a mechanical support system became indicated in those patients whose hemodynamic and clinical condition deteriorated despite treatment with enoximone in addition to maximal sympathomimetic medication. The strategy to administer enoximone routinely was the result of a prospective study on 24 pretransplant patients in whom enoximone therapy reduced the need for mechanical assistance by 62%. At the time of device implantation shock-related organ impairment such as cerebral, renal, hepatic, and respiratory dysfunction was present in 62% of patients. In addition, 7 patients had pneumonia. During mechanical support complete recovery of end-organ failure and resolution of pneumonia was observed in the majority of patients. The results indicate that end-organ dysfunction per se should not be considered a contraindication to mechanical circulatory support as a bridge to cardiac transplantation. However, further clinical investigations are needed to identify predictive indicators of irreversible organ damage.
Cinematics and Sticking of Heart Valves in Pulsatile flow Test
Authors: Köhler J. , Wirtz R.
Published: March 2018

The aim of the project was to develop laboratory test devices for studies of the cinematics and sticking behaviour of technical valve protheses. The second step includes testing technical valves of different types and sizes under static and dynamic conditions. A force-deflection balance was developed in order to load valve rims by static radial forces until sticking or loss of a disc (sticking- and clamping-mould point) with computer-controlled force deflection curves. A second deflection device was developed and used for prosthetic valves in the aortic position of a pulsatile mock circulation loop with simultaneous video-cinematography.

The stiffness of technical valve rims varied between 0.20 (St. Jude) and about 1.0 N/μm (metal rim valves). The stiffness decreased significantly with increasing valve size.

Sticking under pulsatile flow conditions was in good agreement with the static deflection measurements. Hence, valve sticking with increasing danger of thrombus formation is more likely with a less stiff valve rim. In the case of forces acting perpendicularly to the pendulum axis, the clamping mould-point of the valve can be reached, followed by disc dislodgement.
Bioartificial Polymeric Materials Obtained from Blends of Synthetic Polymers with Fibrin and Collagen
Authors: Soldani G. , Mercogliano R.
Published: March 2018

A new class of biomaterials, called “bioartificial polymeric materials”, was prepared blending a segmented polyurethane (PU) with fibrinogen (FBNG); and poly(acrylic acid) (PAA), poly(acrylamide) (PAAM), poly(vinyl alcohol) (PVAL), with collagen (CLG), respectively. The PU-FBNG material was processed through a spraying, phase-inversion technique to fabricate porous tubular conduits. FBNG was subsequently converted into covalently cross-linked fibrin (FBN) through the action of thrombin (Th), fibrin-stabilizing factor (FSF), and calcium ions. Differential scanning calorimetry (DSC) showed the cross-linked blend was more stable than native cross-linked FBN. Tensile behaviors of the PU-FBN materials closely matched those of a natural artery on varying the ratio PU/FBN. Implantation experiments in the rat model showed a mature internal capsule and good tissue organization of PU-FBN (50%) grafts in the regenerated arterial wall. However, 50% of FBN did not assure adequate mechanical resistance, and aneurysmal changes were seen in some grafts. DSC of CLG-based materials, processed by casting, showed that the synthetic component offered definite advantage compared to the CLG denaturation temperature, particularly noticeable for CLG-PAA and CLG-PVAL blends. Material advantages and drawbacks are discussed.