bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesh-Constricted Varicose and Dilated Veins Used as Arterial Bypass Grafts
Authors: Moritz A. , Magometschnigg H. , Ptakovsky H. , Windberger U. , Raderer F. , Grabenwöger F. , Wolner E.
Published: March 2018

To avoid non-autogenous vascular prostheses in coronary and peripheral vascular procedures, otherwise unusable dilated, varicose or thin-walled veins can be implanted as naturally endothelialized grafts after being calibrated by insertion into mesh tubes. In six sheep the 14 mm diameter jugular vein was inserted into a 12 cm long, 6 mm diameter Dacron mesh tube and implanted as a femoropopliteal graft. On the contralateral side the femoral vein with a maximal diameter of 7 to 8 mm was implanted. At control angiography after two months all grafts were patent, none of the wrapped grafts showed wrinkles or signs of anastomotic hyperplasia. Segments of wrapped veins were casted in paraffin under physiological pressure and cut transversely. In all cases the vein wall was pressed against the mesh tubes without forming folds. Mesh-wrapped varicose veins were used for three femorocrural and seven femoropopliteal reconstructions. All grafts showed a smooth flow surface at control angiography. Identations occurred only at sites where thick-walled side branches had been ligated rather than oversewn. One popliteo-pedal reconstruction occluded after two months and one patient with a crural reconstruction died two months after surgery with a patent graft. The remaining grafts were patent after 11 (2-32) months. Oversized veins can be considerably constricted by tubes without forming wrinkles. By this technique varicose veins can be used as bypass grafts and in general vein grafts can be matched in size to the recipient vessel.
Ultrafiltration and Pressure Profiles in Continuous Arteriovenous Hemofiltration Studied by Computerized Scintigraphic Imaging
Authors: Ronco C. , Lupi A. , Brendolan A. , Feriani M. , Crepaldi C. , La Greca G.
Published: March 2018

Clotting of the filters in continuous arteriovenous hemofiltration (CAVH) has been frequently related to filtration pressure equilibrium (FPE). The geometry of the filter and the blood flow, together with filtration fraction, are the factors affecting FPE. A new method based on scintigraphic imaging of the filter is described to demonstrate FPE and identify the operational conditions influencing it. A radiolabelled marker molecule (albumin macroaggregates + Tc99) is added to the blood circulating at various flows through the filter. Changes in the concentration of this molecule detected by a gamma camera are used to calculate the water fluxes in different sections of the filter. When the curve reaches a plateau, no further changes occur and FPE is achieved. The study used Amicon D-30 hemofilters and FPE points were achieved for blood flows of 75, 110 and 150 ml/min respectively 8 cm, 12 cm and 18 cm from the inlet. The study not only demonstrates the occurrence of FPE, but also identifies the length of the filter required at a given blood flow to avoid FPE (achieving less clotting and lower heparin requirement). The Amicon diafilter family, having filters of different length, is useful for “personalizing” the filter in CAVH.
Ex Vivo Removal of IgE in Atopic Asthma by Extracorporeal Plasmoimmunoadsorption (EPIA): Development of a Clinical Adsorbent
Authors: Lebedin Y.S. , Gorchakov V.D. , Petrova E.N. , Kobylyansky A.G. , Raudla L.A. , Tatarsky A.R. , Bobkov E.V. , Adamova I.Y. , Vasilov R.G. , Nasonov E.L. , Pokrovsky S.N. , Chuchalin A.G.
Published: March 2018

We have developed an immunoadsorbent (IA) for ex vivo removal of IgE after in vitro screening of matrix (Sepharose and tresyl-activated Toyopearl) and ligand (monospecific rabbit polyclonal anti-lgE antiserum and monoclonal antibodies (Abs) or their Fab fragments). Specific adsorptive capacity (SAC) for IgE was maximal in Sepharose-based IA with both types of Abs. Fab-containing IA on Sepharose retained 70-90% of the SAC of native Ab-containing IA. Toyopearl-based IA showed comparable SAC under static conditions but worked unsatisfactorily under continuous flow conditions. To assess the complement-activating capacity (CAC) of IA in vitro anaphylatoxin (C3a, C4a, C5a) generation was applied. CAC was directly related with the amount of immobilized Ab ligand, without depending on Ab specific activity. Fab-containing IA showed more CAC than native Ab-containing IA, and polyclonal IA more than monoclonal IA. Therefore, IA for IgE apheresis were prepared from native monoclonal Abs and CNBr-activated Sepharose CL 4B under aseptic conditions and packed into a glass column. This IA was used in 17 clinical IgE apheresis treatments of five atopic asthma patients. No substantial side effects were observed; in vivo IA effectively removed IgE from plasma (83 to 98%).
Cellular Mechanisms of Artificial Peptides Binding to HLA
Authors: Frumento G. , Pernis B. , Fais F. , Vitale M. , Chersi A. , Ferrara G.B.
Published: March 2018

On the basis of the consideration that cell-free models cannot precisely mimic the complexity of the intracellular environment, we used a system to investigate the mechanisms that enable antigen-presenting cells (APC) to bind exogenous peptides through their human leukocyte antigen (HLA) molecules. We evaluated the uptake of the radiolabeled peptide 17-29-Tyr of influenza virus matrix protein by B-EBV cell lines, under various conditions. The results can be summarized as follows: a) the kinetics of peptide binding and release are very fast in living, fully competent cells; b) the peptide-HLA complexes are short-living and the DR molecules continuously undergo peptidic exchange; c) using glutaraldehyde-fixed cells, the kinetics of the two phenomena are slow, closely resembling those observed with the same peptide and purified, immobilized DR molecules.

The data suggest that in APC, cellular mechanisms are operative that increase the efficiency of both loading and unloading of Class II HLA with exogenous peptides. This is likely to be related to the recycling of Class II molecules to intracellular compartments, were binding takes place.

The observation that the HLA-peptide complex is a dynamic structure, suggests the possibility of replacing natural peptides with synthetic ones at this level, in order to regulate the immune response.
Fluid-Shift during Computer-Modulated Profile Hemodialysis (Cmp-Hd)
Authors: Keuchel M. , Dittmar A. , Saure B. , Laage C. , Ebel H. , Lange H.
Published: March 2018

Computer-modulated profile hemodialysis was examined for patients' comfort and fluid-shift. Fifteen patients were studied after two weeks of dialysis with each of the following profiles: A): constant ultrafiltration (UF) and dialysate sodium (138 mmol/l); B): decreasing UF; C): decreasing UF and decreasing high dialysate sodium (starting 10% above serum-sodium, with a gradual reduction to 138 mmol/l in the fourth hour). Patients with a calculated increase of intracellular volume (ICV) during dialysis had more complaints after dialysis than the others. ICV decreased in all patients with low serum-sodium (<136 mmol/l) during all profiles, whereas in patients with higher sodium, only profile C led to a decrease of ICV. However, interdialytic weight gain increased about 75% in patients with low serum-sodium under profile C. The sodium profile could help in preventing imbalance without side effects in patients with high sodium. (Int J Artif Organs 1991; 14: 630-3)
Importance of Purification on Transfusional Efficacy of Hemoglobin Solutions
Authors: Menu P. , Labrude P. , Grandgeorge M. , Vigneron C.
Published: March 2018

It has only been realized quite recently how important is the purification of hemoglobin solution for use in transfusion and several techniques have been published. We used ion exchange chromatography with which the main “contaminants” (glycoproteins, enzymes, phospholipids) are absorbed by the gel, whereas hemoglobin is not retained. The solutions studied here are non-modified hemoglobin and its homologue pyridoxylated hemoglobin (PLP-Hb).

Physico-chemical analyses, usually undertaken to characterize hemoglobin solutions, show no difference before and after purification, except that the enzymatic activity almost disappears. In order to appreciate the benefits of purification, total exchange transfusions were carried out on rats. Without reperfusion, purification of the hemoglobin solution allowed a significantly longer survival time which was even more significant with PLP-Hb solution. Urinary loss did not seem to be affected by purification. With reperfusion in order to compensate these renal losses, PLP-Hb solutions gave survival times up to three days. However, the inevitable death of the animals poses the problem of instability of these purified solutions following enzyme loss.
Detection of Charges and their Distribution on Dialysis Membranes with Cationic/Anionic Dyes Using Confocal Laser Scanning Microscopy
Authors: Thomaneck U. , Vienken J. , Waldschläger U. , Diamantoglou M. , Schütt W. , Falkenhagen D. , Klinkmann H.
Published: March 2018

Methods for the detection of positive or negative charges on the surface of biomaterials/membranes and inside a membrane are important for the characterisation of such materials. We tested different dyes and optimized staining procedures. Under standardized conditions negatively charged membranes were stained with cationic triarylmethane compounds such as crystal violet and positively charged membranes with the anionic anthraquinone dye anthralan blue B. There was no staining of uncharged cellulose membranes. The applicability of these methods was demonstrated on membranes coated to varying degrees with charged compounds such as heparin, these changes in charge being detectible quantitatively by photometry. The distribution of charges inside a membrane was detected by optical sectioning across the stained (FITC labelled poly-L-lysine) membrane using confocal laser scanning microscopy (LSM). LSM offers a completely new application possibility in biomaterial and biocompatibility research.
Effect of Neo Red Cells on the Canine Hemorrhagic Shock Model
Authors: Usuba A. , Motoki R. , Miyauchi Y. , Suzuki K. , Takahashi A.
Published: March 2018

This study evaluated the newly developed artificial red blood cells named Neo Red Cells (NRC) after hemorrhagic shock in mongrel dogs. NRC is prepared as microcapsules by a method in which stroma-free hemoglobin is encapsulated using a bimolecular lipid membrane called liposome. The particle size is 0.2 μm, methemoglobin content is less than 5% and the hemoglobin concentration is 5.6 g/dl.

We analyzed blood gases and hemodynamics and carried out laboratory examinations after 59-88% blood exchange using NRC. The hemodynamic parameters returned to the normal range after NRC. Inhaling normal room air, oxygen carried by NRC was 60.40% at the exchange rate of 88%. Renal and hepatic function and other laboratory findings were normal after administration of NRC. After further study and improvement NRC could be considered suitable as artificial blood for treatment of hemorrhagic shock.
Extracorporeal Membrane Oxygenation (Ecmo): Extended Indications for Artificial Support of Both Heart and Lungs
Authors: Jurmann M.J. , Averich A. H , Demertzis S. , Schaefers H.J. , Zahner H.H. , Endrigkeit K.D. , Wahlers T. , Cremer J. , Borst H.G.
Published: March 2018

Extracorporeal membrane oxygenation (ECMO) was used to achieve temporary artificial support in cardiac and pulmonary function in 22 patients from 1987 to September 1990. Standard indications were postcardiotomy cardiogenic shock (n=4), neonatal (n=1) and adult respiratory distress syndrome (n=4). ECMO was also used for extended indications, such as graft failure following heart (n=11) or lung transplantation (n=2). In six of these cases ECMO was instituted as a bridge device to subsequent retransplantation of either the heart (n=4) or one lung (n=2). One out of nine patients supported by ECMO for standard indications, and two out of 13 patients supported for extended indications are long-term survivors. This series illustrates the results with ECMO in emergency situations, in patients under immunosuppressive protocols, or in patients with advanced lung failure requiring almost complete artificial gas exchange. In such complex situations, ECMO does provide stabilization until additional therapeutic measures are in effect. ECMO cannot be recommended for postoperative cardiogenic shock but short-term ECMO support is an accepted method in most cases with graft failure or pulmonary failure or other origin.
Calves Chronically Implanted with a Total Artificial Heart as a Pharmacological Model
Authors: Everett S.D. , Pantalos G.M. , Goldenberg I.F. , Long J.W. , Robison P.D. , White R.K. , Landa M.S. , Shaw W.J. , Olsen D.B.
Published: March 2018

Pharmacological therapy for congestive heart failure includes drugs that have both inotropic and vasoactive effects, although it is sometimes difficult to differentiate between the two effects. An animal with an implanted total artificial heart (TAH) allows the investigation of the vascular effect of these drugs in the absence of the effect on the myocardium. An advantage of the TAH model is its sensitivity to changes in right and left ventricular preload and afterload. Four instrumented TAH calves were given vasoactive drugs and the response was compared to control. Epinephrine, dopamine, isoproterenol, and nitroprusside were selected because of the predictability of their responses. Epinephrine caused a significant increase in systemic vascular resistance (SVR), and dopamine caused a significant increase in Pulmonary vascular resistance (PVR) and Isoproterenol caused a significant decrease in PVR. TAH implanted calves can thus serve as a pharmacological model to study the vascular response, which may be useful in investigation of new agents with inotropic and vascular effects.
Immunoprotection of Pancreatic Islet Grafts within Artificial Microcapsules
Authors: Brunetti P. , Basta G. , Faloerni A. , Calcinaro F. , Pietropaolo M. , Calafiore R.
Published: March 2018

To circumvent pancreatic islet graft-directed immune destruction we enveloped porcine islets within highly biocompatible and selectively permeable algin/polyaminoacid microcapsules. These special microspheres were deposited between the inner (permeable) and the outer (impermeable) layers of an artificial, coaxial vascular prosthesis, directly anastomized to blood vessels. Five dogs with spontaneous, insulin-dependent diabetes received microencapsulated porcine islets in arterio-vein iliac prosthesis by-passes. One showed complete and the remainder partial, sustained reversal of hyperglycemia. Microencapsulation may be a potential solution to immunological problems related to islet transplantation.
Pseudomonas Septicemia Due to Deficient Disinfectant Mixing during Reuse
Authors: Vanholder R. , Vanhaecke E. , Ringoir S.
Published: March 2018

We describe a cluster of four septicemias with pseudomonas, that occurred in a unit performing formaldehyde reuse of capillary dialyzers. Samples of blood, heparin solutions, dialysate and effluent of reused dialyzers, were evaluated bacteriologically and upon the adequacy of the reuse procedure. Pseudomonas aeruginosa, vesicularis and/or xanthomonas maltophilia were found on the blood cultures obtained during the septicemic reactions, and in the effluent of two reprocessed dialyzers not yet used (> 104 CFU/ml). These two dialyzers had also extremely low formaldehyde concentrations (0.0014 and 0.005% versus the expected 4%). Membrane and antibiogram characteristics of a Pseudomonas aeruginosa strain, recovered from the blood cultures in one patient, and of a strain found in the effluent of one of the two contaminated reprocessed dialyzers, were the same. The problem was attributed to the inadequate mixing of the disinfectant with the tap water used in the automated reprocessing device, in the absence of an alarm disclosing this failure.
Calibration of a Wearable Glucose Sensor
Authors: Schmidt F.J. , Aalders A.L. , Schoonen A.J.M. , Doorenbos H.
Published: March 2018

Calibration of glucose sensors proved difficult for electrodes with immobilized glucose-oxidase. The correlation between the sensitivity of the electrodes in vitro and in vivo appeared to be poor. We developed a new type of glucose sensor, based on a microdialysis system, in which an oxygen electrode is used as detector outside the body and the enzyme glucose-oxidase dissolved in water is used as a dynamic selector. The enzyme solution is pumped through a hollow fiber placed subcutaneously, before the fluid passes the detector. The glucose sensor was tested in the subcutaneous abdominal tissue of 12 healthy volunteers and 12 type I diabetic patients. Blood glucose was clamped at two levels to permit a two-point calibration of the sensor in vivo. These values correlated well with the in vitro calibration factors (r=0.949). In subcutaneous tissue the sensor measures 43 ± 9% of the blood glucose value, using the in vitro calibration factor. No differences were detected between healthy volunteers and diabetic patients.
In Vitro Methods to Evaluate Metal-Cell Interactions
Authors: Ciapetti G. , Roda P. , Landi L. , Facchini A. , Pizzoferrato A.
Published: March 2018

The aim of this study was to test different metals, widely employed in constructing prosthetic devices, by in vitro methods. Biological effects of such materials were analysed through four different assays on human lymphocytes and granulocytes. The lymphocyte proliferation assay gave quantitative results, while the viability test showed the morphological appearance of the cells correlated well with previous results. NK cytotoxicity and granulocyte chemokinesis tests provided interesting data on leucocyte performance when challenged with metals. Therefore the present study adds new basic information on cell behaviour when metal products are present in the body, e.g. around devices implanted in human tissues
Chronic T-Lymphocyte Activation in Chronic Renal Failure: A Study of Hemodialysis, Capd and Pre-Dialysis Patients
Authors: Caruana R.J. , Leffell M.S. , Lobel S.A. , Campbell H.T. , Cheek P.L.
Published: March 2018

In this study we measured indices of T-lymphocyte activation in normal volunteers, chronic hemodialysis patients, CAPD patients and chronic renal failure patients not yet on dialysis. Serum IL-2 levels were elevated in patients compared to controls. Soluble IL-2 receptors were elevated in all three patient groups and were highest in CAPD patients. Clearance of IL-2 and soluble interleukin receptors was negligible in dialysis and renal failure patients. Hemodialysis patients had a significantly lower percentage of CD3-positive cells than all other groups. Hemodialysis with a variety of membrane/bath combinations did not significantly affect any of the parameters measured. This study provides some support for the hypothesis that chronic T-cell activation is present in renal failure.
Mechanical Bridge to Transplantation with the Vienna Heart in TAH and LVAD Configuration
Authors: Moritz A. , Rokitansky A. , Schima H. , Prodinger A. , Laufer G. , Hiesmayer M. , Wolner E.
Published: March 2018

The Vienna heart uses a vacuum formed, pellethane pulsatile ventricle and is available in left ventricular assist (LVAD) and total artificial heart (TAH) configurations. This device was used as mechanical support of the failing heart in nine patients intended for heart transplantation. In two patients with cardiomyopathy an orthotopic TAH was implanted; one survived despite severe preoperative ischemic liver damage, and the other died of sepsis.

In seven patients an atrio-aortic LVAD was implanted; six had suffered an acute myocardial infarction with cardiogenic shock, and one could not be weaned off bypass. Three patients survived. These included one 65-year-old with incipient ARDS at operation, and a 40-year-old with preoperative liver and kidney insufficiency who was transplanted in septicemia. In this patient the septic focus, natural and artificial heart, were removed at transplantation.

Four patients died. In one we were unable to establish satisfactory circulation, one died after failure of the transplanted heart, one suffered a lethal cerebral embolism and one developed multi-organ failure after repeated attacks of ventricular fibrillation.

With the Vienna heart sufficient circulatory support could be established with cardiac outputs between 6 and 8 l/min for the TAH and 3.5 to 4.5 I/min for the LVAD. With this type of support an overall survival rate of 44% could be achieved. Mechanical hemolysis was not a clinical problem and no device failure occurred.
Spontaneous Dialytic Ultrafiltration with Intraperitoneal Reinfusion of the Concentrate in 15 Cirrhotic Patients with Intractable Ascites
Authors: Cadranel J.F. , Grippon P. , Gargot D. , Lunel F. , Bernard B. , Valla D. , Opolon P.
Published: March 2018

The clinical efficacy and tolerance of dialytic ultrafiltration of ascites through a hemofilter (DUF) with peritoneal reinfusion of the concentrate was evaluated in 15 cirrhotic patients with intractable ascites. All together, 51 DUF procedures were carried out. An average of 8.6 was ultrafiltered during 12 h with no significant change in blood pressure, hemoglobin, coagulation parameters or plasma creatinine. A significant increase in ascitic protein concentration was observed immediately after the procedure and a slight but significant increase in 24 h urinary output. A controlled evaluation of DUF compared to large paracenteses seems to be justified by these preliminary results.
In Vitro Endothelialization of Carbon-Coated Dacron Vascular Grafts
Authors: Bernex F. , Mazzucotelli J.P. , Roudiere J.L , Benhaiem-Sigaux N. , Leandri J. , Loisance D.
Published: March 2018

Physical vapour deposition is used to coat vascular prostheses with pyrolytic carbon. This coating may facilitate the development of an endothelial monolayer in grafts implanted in laboratory animals. This in vitro study compared the adherence and growth of cultured porcine aortic endothelial cells (EC) seeded in vitro on carbon-coated Dacron, to uncoated prostheses. The cells were incubated at 5 × 104 cells/cm2. Progress was monitored at different times (TO + 2 hours, D 1, D 4, D 8) by microscopic observation, when cell counts were made; and by scanning electronic microscopy (SEM) to evaluate morphological EC-graft interactions. Cell adherence was independent of the carbon coating but cellular growth occurred only on carbon-coated Dacron. The SEM observations showed both the shape of the adherent cells, which were rounded on uncoated Dacron and extensively spread on carbon-coated prostheses, and the morphology of the carbon coating.
Improved Immunoglobulin Production in Dialysis Patients Treated with Recombinant Erythropoietin
Authors: Schaefer R.M. , Paczek L. , Berthold G. , Gilge U. , Heidland A.
Published: March 2018

Improvements in B lymphocyte function have been reported in hemodialysis patients receiving erythropoietin. The present investigation studied whether erythropoietin interferes with B cell function and the mechanisms of this effect. Antibody production by cultured peripheral blood mononuclear cells (PBMC) (7 days) from 15 dialysis patients before and during erythropoietin treatment and from 14 healthy controls was followed. IgG and IgA were formed less in the uremic group than in healthy subjects. After 8 weeks of erythropoietin (hematocrit rose from 19 to 31%) basal IgG formation by PBMC rose from 304 ± 83 to 566 ± 49 ng/ml (p<0.02), while IgA production rose from 380 ± 121 to 563 ± 362 ng/ml (p<0.01). IgM production, which appeared to be normal in uremia, remained unchanged during erythropoietin treatment. Production of IgG and IgA stimulated by pokeweed-mitogen was subnormal in uremia, but improved under erythropoietin therapy. To establish whether erythropoietin acted by itself or through correction of the renal anemia, healthy PBMC were directly incubated with 2 U/ml of erythropoietin. Under these conditions production of IgG (+19%), IgA (+28%), and IgM (+32%) was enhanced. Taken together these data indicate a direct stimulant effect of erythropoietin on B lymphocytes in end-stage renal failure.
Continuous Ionography (CIG) in Haemodialysis by Ion-Selective Carrier Membrane Electrodes (ISCME) with Solid Cement Contact for Flow-Through Measurement
Authors: Kuhlmann U. , Gräf R. , Schindler J. , Lange H.
Published: March 2018

Ion balance is of particular interest for patients maintained on RDT because of the importance of controlling ion movement and ion removal during haemodialysis. Continuous ionography (CIG) was therefore tested for electrolyte monitoring in extracorporeal haemodialysis in vitro and in vivo. The accuracy and stability of the electrodes were examined and various concentrations of potassium in blood, ultrafiltrate and dialysate were evaluated. Ion selective carrier membrane electrodes (ISCME) appeared to be suitable for continuous and simultaneous measurement of ions in blood and dialysis fluid. CIG monitoring of ion movement and ion removal could be the basis for adjusting and computer-managing ion elimination during extracorporeal haemodialysis.
Specific Removal of Transthyretin from Plasma of Patients with Familial Amyloidotic Polyneuropathy: Optimization of an Immunoadsorption Procedure
Authors: Regnault V. , Costa P.M.P. , Teixeira A. , Rivat C. , Stoltz J.F. , Saraiva M.J.M. , Costa P.P.
Published: March 2018

Familial amyloidotic polyneuropathy is characterized by the presence in patients plasma of a genetic variant of transthyretin. No specific treatment has been found and extracorporeal immunoadsorption on immobilized anti-transthyretin antibodies appears as a potentially attractive procedure.

Parameters involved in specific immunoadsorption of transthyretin were studied and optimized. Several monoclonal anti-TTR antibodies were compared as affinity ligands and one of them was found to be suitable for such purposes. Optimum quantities of antibodies to be immobilized on the gel were determined. Three desorption agents were tested for regenerating immunoadsorbents and best results were obtained with basic variation of pH, allowing total desorption of TTR and possibility of multiple use without loss of adsorption capacity.

Simulation of an immunoadsorption procedure in well-defined conditions showed efficiency and specificity of adsorption to remove TTR and the system thus should be subjected to clinical trials.
Control of Oral Anticoagulation in Patients Using Long-Term Internal Jugular Catheters for Haemodialysis Access
Authors: Besley M. , Thomas A. , Salter S. , Sang Y.Y. , Vas M. , Uldall P.R.
Published: March 2018

Patients using long-term double-lumen silastic jugular catheters for haemodialysis access frequently require oral anticoagulants to maintain patency of the catheter. It may be difficult or impossible to obtain peripheral vein blood samples for PT measurements to regulate the oral anticoagulant dose. Our studies have shown that removal of 3 mis of blood from the catheter limb containing the heparin (to be discarded) followed by 10 mis as a heparin wash-out (to be returned to the patient) allows blood to be taken from the arterial limb of the catheter for PT measurement. The PT measurement obtained from the arterial limb after a 10 ml wash-out is nearly always identical with the PT measurement on blood obtained from a peripheral vein. If the simultaneously measured aPTT is normal the PT is predictably and consistently accurate. If the aPTT is raised due to traces of residual heparin then the PT may be inaccurate and should be repeated. This method is easy and reliable and can be recommended as an aid to regulation of the oral anticoagulant dose
Improved Endothelialization of Postfixation Treated Biological Vascular Grafts
Authors: Moritz A. , Grimm M. , Eybl E. , GrabenwöGer M. , Böck P. , Siegl H. , Wolner E.
Published: March 2018

Preliminary in vitro and in vivo studies have shown that endothelialization is improved by a detoxifying postfixation treatment of glutaraldehyde (GA) fixed bovine pericardial patches and grafts.

To test whether this is also true for GA tanned human vein (HUV) grafts, patches of commercially available HUV grafts (MHUV), postfixation treated HUV grafts (PTHUV) and GA fixed HUV granfts (GAHUV) were endothelialized in vitro. Eight pairs of MHUV and PTHUV grafts were implanted as femoropopliteal grafts in eight sheep. Endothelial cell adherence was significantly better on PTHUV (11910 ± 4413 cells/cm2) than on MHUV (6545 ± 2835 cells/mm2; p = 0.0007) and on GAHUV (3563 ± 1638; p = 0.0001) one day after cell seeding. After eight days of culture significantly more cells spread on PTHUV material than on MHUV (p = 0.0002), but none of the cultures on GAHUV remained viable. Four PTHUV grafts occluded in the femoropopliteal position, mostly because of kinking, so that only in four pairs of grafts could the thrombus-free surface be compared by planimetry. Again PTHUV material was covered more by endothelial cells than was MHUV material. On PTHUV endothelial cells spread directly on the graft material while on MHUV these cells spread on a layer of fibrin and macrophages.

Postfixation treatment of GA-fixed biological graft material by aminoacid solutions improves the biocompatibility of the material and enhances in vitro as well as spontaneous in vivo endothelialization.
The Applicability of Experimental Experience with the Total Artificial Heart to its Clinical Use
Authors: Vašků J. , Urbánek P. , Dostál M. , Vašků Jan
Published: March 2018

Long-term experiments with the total artificial heart (TAH) are a source of valuable knowledge for later clinical application. Our observations result from 66 long-term experiments on calves and one goat ranging from 30 to 314 days, which have shown the main possible complications in the early period (one month) and later in the experiment. Problems until the second month of pumping concern the clinical pendant of the TAH as a bridge for transplantation, i.e. surgical problems, blood coagulation disorders, infection etc. Later problems are high venous pressure or arterial hypertension, infection with septic thromboembolization, mineralization of the driving diaphragm, etc., and are more closely comparable to the conditions of permanent clinical use of the TAH. Faultless surgery, device function and the regimen of pumping are essential factors in every long-term experiment, just as in clinical application. Infection is a threat throughout any experiment, as in clinical cases. The TNS-BRNO-VII/clin/80 TAH has been implanted in six patients.
A New Central Supply System as Alternative Source for Bicarbonate Dialysate
Authors: Rehmert N. , Böcker T. , Raidt H. , Langer K. , Graefe H.
Published: March 2018

Bicarbonate dialysis is mandatory for high efficiency treatment. In most cases bicarbonate is delivered either as prepacked powder or as a stable liquid concentrate in 6-10 I plastic containers. With a newly designed central supply system (CSS) using 800 I tanks of custom-made sterile and pyrogen free concentrates, we investigated the risk of bacterial contamination of dialysate in a 30-bed dialysis unit. During three months, samples of reverse osmosis (RO) water, concentrates and dialysate were taken every two weeks. Colony forming units (CFU) were counted after 48 h incubation. Further samples were taken during nine months of continuous use of the CSS without further intermittent disinfection. None of the samples had > 10/ml CFU. Pseudomonas, corynebacteriae and enterobacter were the predominant species. In summary, this CSS proved reliable in providing bacteriologically safe bicarbonate dialysate as defined by international standards (CFU < 200/ml). It significantly reduces costs, workload and environmental pollution by plastic waste.
Correlation of Blood Pressure in End-Stage Renal Disease with Platelet Cytosolic Free Calcium Concentration during Treatment of Renal Anemia with Recombinant Human Erythropoietin
Authors: Schiffl H.
Published: March 2018

The hemodynamic hallmark of hypertension complicating the treatment of renal anemia with recombinant human erythropoietin (rHu-EPO) is increased total peripheral vascular resistance, but the mechanisms underlying the arteriolar vasoconstriction are still an enigma. We studied body fluid volumes, plasma renin activity, plasma norepinephrine, and calcium metabolism in platelets in 40 previously normotensive hemodialysis patients before and after 12 weeks of rHu-EPO treatment. Partial correction of anemia caused a rise in arterial pressure (94 ± 6 mmHg vs 124 ± 7 mmHg, p < 0.05) and in platelet cytosolic calcium concentration (113 ± 5 nM vs 171 ± 18 nM, p < 0.05) in eight patients. Hypertensive patients had significantly higher plasma noradrenaline concentrations, but they did not differ significantly in body fluid volumes and plasma renin activities. There was a close correlation between free calcium concentration in platelets and mean arterial pressure in patients developing rHu-EPO-induced-hypertension (r = 0.95). Short-term antihypertensive treatment resulted in a reduction of free calcium concentrations in platelets and a concomitant fall in blood pressure. The main results of the present studies suggest that rHu-EPO-induced hypertension might be associated with altered cellular calcium homeostasis and hyperactivity of the sympathetic nervous system. If rHu-EPO therapy induces alterations of pressor factors or the hormone itself raises the cytosolic calcium not only in platelets but also in vascular smooth muscle cells, altered cellular calcium influx may contribute to the arteriolar vasoconstriction.
Hypoglycemia in Diabetics on Dialysis with Poor Glycemic Control: Hemodialysis versus Continuous Ambulatory Peritoneal Dialysis
Authors: Tzamaloukas A.H. , Murata G.H. , Eisenberg B. , Murphy G. , Avasthi P.S.
Published: March 2018

Eight diabetic men with poor glycemic control, probably worsened by severe congestive heart failure and gastroparesis, were sequentially dialyzed by CAPD and hemodialysis. Mean blood glucose concentration, blood glycosylated hemoglobin, and insulin dose were higher during CAPD than during hemodialysis. Among blood glucose determinations, however, the frequency of hypoglycemia (glucose <3.3 mmol/L) was higher during hemodialysis (13.2 ± 8.9%) than during CAPD (2.8 ± 2.1% p = 0.012), whereas the frequencies of hyperglycemia (glucose >11.1 mmol/L) and euglycemia (glucose between 3.5 and 11.1 mmol/L) did not differ between the two dialysis modalities. Furthermore, hypoglycemia was severe during hemodialysis and was associated with two deaths. There were no deaths linked to abnormalities in blood glucose concentration during CAPD. When hypoglycemia is frequent in diabetics with poor glycemic control, CAPD is preferable to hemodialysis.
Lung Involvement in Systemic Sclerosis Sine Scleroderma Treated by Plasma Exchange
Authors: Ferri C. , Bernini L. , Gremignai G. , Latorraca A. , Fazzi P. , Tavon A. , Solfanelli S. , Bombardieri S.
Published: March 2018

Systemic sclerosis sine scleroderma can present in some patients as pulmonary interstitial fibrosis. Until now ten cases with this particular clinical variant, all men, have been reported in the literature. The knowledge of systemic sclerosis sine scleroderma presenting as lung interstitial involvement is important in clinical practice for an early diagnosis and correct therapeutic strategy. This work reports the clinico-serological features of two further cases, one a woman, of systemic sclerosis sine scleroderma with prevalent lung involvement, and describes the effects of therapeutic plasma exchange.
Stapedius Reflex in Patients with an Inner Ear Prosthesis
Authors: Stephan K. , Welzl-Muller K.
Published: March 2018

The stapedius reflex elicited by electrical stimulation was investigated in 21 deaf individuals supplied with an inner ear prosthesis. All patients were implanted with the Vienna cochlear implant using intra or extracochlear electrodes. Analog stimulation with sinus bursts of various durations (25, 50, 100, 300, 500 ms) and frequencies (125, 500, 1000, 2000 Hz) was used. The time course of the contralateral acoustic reflex was monitored using a fast-response impedance meter. The stapedius reflex was observed in about half of the cases. Reflex threshold was observed at a stimulation level close to uncomfortable loudness. The time course in case of electrical stimulation differs in some aspects (rise time, onset) from acoustic stimulation in hearing individuals. Temporal integration of the stapedius reflex was observed also in case of electrostimulation through the cochlear implant.
Model-Based Decision Support System for Individual Prescription of the Dialysate Bicarbonate Concentration in Hemodialysis
Authors: Thews O.
Published: March 2018

A decision support system has been developed that determines the optimal dialysate bicarbonate concentration in hemodialysis therapy for each patient individually. The knowledge about the behavior of the acid-base state during treatment has been provided by a mathematical model for the description of dynamic exchange processes during hemodialysis. This model simulates the sodium and water distribution, the acid-base state as well as the ventilation. The decision support system uses the model for the prediction of the end-dialysis acid-base state and calculates by means of linear optimization the dialysate bicarbonate concentration which is necessary to reach a specified end-dialysis state. If the aspired acid-base state can not be reached, the system varies the dialysate sodium concentration and the treatment time. The whole program can be used on a PC and is easy to use. One decision making process lasts between 10 seconds and 5 minutes depending on the computer.
Differences between KT/V Measured during Dialysis and KT/V Predicted from Manufacturer Clearance Data
Authors: Saha L.K. , Van Stone J.C.
Published: March 2018

We retrospectively analyzed data from 3,863 dialysis treatments in 329 end-stage renal disease patients over a period of 33 months to evaluate the accuracy of in vitro KT/V estimated by manufacturer's urea clearance data in relation to in vivo measured KT/V. In 1,087 urea clearances measured, mean actual clearance was 87% of predicted. At all blood flows, actual clearances were significantly lower than predicted (8-16% lower than predicted). In 2,807 KT/V measurements, predicted KT/V was 1.238 ± 0.005 whereas the mean of actual measured KT/V was 16% lower or 1.024 ± 0.005 (P < 0.0001). At different blood flows and with different dialyzers, predicted KT/V overestimated actual values. With increasing numbers of reuse, actual/predicted clearance ratios and actual/predicted KT/V ratios progressively dropped. Prescribing dialysis treatments using manufacturer's in vitro generated clearance data can lead to marked underdialysis of patients.
Electromechanical Artificial Heart with a New Gear Type and Angled Pump Chambers
Authors: Kaufmann R. , Reul H. , Rau G.
Published: March 2018

The intrathoracic anatomical situation after explantation of the natural heart defines the maximum available space for the design of the housing as well as of the inlet-and outlet connectors of a fully implantable electromechanical artificial heart. Based on computer-assisted anatomical studies, a total artificial heart housing is designed which facilitates an oblique orientation of the pumping chambers for a better fluidmechanical and anatomical arrangement of the in- and outlet connectors. The pumping chamber geometry is based on modifications of an existing cardiac assist-system. Subsequently a mechanical gear which conforms to this anatomically adapted housing is developed.
Dynamic Cardiomyoplasty in a Patient with End-Stage Cardiomyopathy
Authors: Zabala M.S. , Herreros J. , Gil O. , Iglesias I. , Barba J. , Alegría E.
Published: March 2018

Dynamic cardiomyoplasty is a relatively new surgical procedure by which a transformed fatigue-resistant skeletal muscle wrapped around the heart is stimulated to contract in synchrony with it, thereby augmenting the ventricular functions of a failing heart. We performed a cardiomyoplasty with latissimus dorsii (LD) in a patient who was refused the heart transplant programme because of pulmonary hypertension and psychosocial contraindications. The patient was 34 years old, functional class grade IV of the New York Heart Association (NYHA), with a three-month history, due to ischemic cardiomyopathy with multiple vessels affected, 10% ejection fraction, arteriolar pulmonary resistance of 7.5 U Wood. Cardiomyoplasty was performed after training the LD muscle for four weeks. One week later the pacemaker was programmed in a DDD mode: amplitude 3.75 V, pulse duration 0.50 ms, AV delay 175 ms. The patient reached functional class grade I-II (NYHA). Inotrope support was discontinued and great clinical improvement was noted. The ejection fraction rose from 10% to 30%. Echocardiographic left ventricular outflow tract velocity increased from 0.33 m/s to 0.60 m/s. These values were compared with radionuclide angiocardiography and echocardiography evaluations. The great clinical improvement and positive changes in left ventricular parameters suggest that cardiomyoplasty is useful in the treatment of some cases of dilated or ischemic cardiomyopathy as an alternative to heart transplantation. Long term follow-up is necessary to evaluate this procedure.
Mechanical Issues in Vascular Grafting: A Review
Authors: Brossollet L.J.
Published: March 2018

Despite intensive research, the success of artificial small-diameter vascular grafts has yet to match that of natural grafts like the saphenous vein. One of the possible reasons is mechanical mismatch of the graft to the host vessel. The study of compliance (dilatability under pressure) has not been conclusive, especially after a series of recent investigations on vein graft evolution. Lately, the focus has been shifting towards more detailed characteristics, like anastomic behaviour, longitudinal elasticity, and flow-related variables. When the relevant property is identified, it should be included in the criteria for design and use of vascular prostheses.
Hemodialysis with Defibrotide: Effects on Coagulation Parameters
Authors: Filimberti E. , Cinotti S. , Salvadori M. , Amato M. , Longo G. , Nazzari M. , Morfini M.
Published: March 2018

In a crossover study conducted with eight uremic patients maintained on hemodialysis, the Authors compared the effects of heparin (100 IU/kg at the start of dialysis) and defibrotide (400 mg at the start, repeated at 2 hours of ongoing dialysis) on the parameters of blood coagulation (VIII:C, AT III, TAT, PC antigen and activity, PS, and FPA), each being assessed before dialysis and at 2, 3 and 4 hours of the ongoing procedure. Heparin-assisted dialysis resulted in a significant rise of VIII:C and AT III; with defibrotide, instead, there was evidence of thrombin activation (increased FPA and TAT). PC levels were raised with both dialysis modalities; however, PC activity and PS levels were increased only in defibrotide-assisted dialysis. There were no adverse reactions or evidence of fibrin formation. These results confirm the antithrombotic activity of defibrotide in the course of dialysis and indicate that this action is independent of thrombin neutralization.
Estimation of the following Cardiac Output Using Sympathetic Tone and Hemodynamics for the Control of a Total Artificial Heart
Authors: Yambe T. , Nitta S. , Katahira Y. , Sonobe T. , Naganuma S. , Akiho H. , Kakinuma Y. , Izutzu K. , Kikuchi Y. , Naganuma T. , Kobayashi S. , Matsuzawa H. , Tanaka M. , Miura M. , Sato N. , Fukuju T. , Mohri H. , Yoshizawa M. , Takeda H.
Published: March 2018

A sympathetic neurogram is potentially useful for the development of a real time total artificial heart (TAH) control system. We used sympathetic tone and hemodynamic derivatives to estimate the following cardiac output in acute animal experiments using adult mongrel dogs. Moving averages of the mean left atrial pressure and mean aortic pressure were used as parameters of the preload and afterload, respectively. Renal sympathetic nerve activity (RSNA) was employed as a parameter of sympathetic tone. Equations for the following cardiac output were calculated using multiple linear regression analysis of the time series data. A significant correlation was observed between the estimated and following measured cardiac output. These results suggest the potential usefulness of the sympathetic neurogram for the real time TAH automatic control system.
Results of Randomized Mitral Valve Replacement with Mechanical Prostheses after 15 Years
Authors: Schulte H.D. , Horstkotte D. , Bircks W. , Strauer B.E.
Published: March 2018

Between 1974 and 1976 150 consecutive patients (pts) were operated on for isolated mitral valve replacement (MVR). Björk-Shiley (BS), Lillehei-Kaste (LK), and Starr-Edwards (SE) (type 6210) prostheses were implanted at random. All survivors were prospectively followed by regular clinical examinations every 6 to 12 months for 15 years. The mean follow-up time was 14.8 years. A constant subjective improvement after 15 years was reported in 62% of pts with BS, 30% with LK, and 49% with SE. The cumulative 14-year survival rate was 0.62 ± 0.13 (BS), 0.56 ± 0.16 (SE), and 0.54 ± 0.15 (LK), respectively. Late mortality was due to thromboembolic events (n=3), bleeding complications (n=3), congestive heart failure (n=7), documented arrhythmias or sudden death (n=6). Thrombotic valve thrombosis (1 BS, 1 LK, 2 SE) required reoperations. Linearized cumulative rates after 14 years for thromboembolic complications were 14.2 ± 3.1 (BS), 15.8 ± 3.7 (SE), 24.3 ± 4.2 (LK). The cumulative risk of severe bleeding complications was not different: BS: 35.8, LK: 35.2, SE: 34.3. During the first years of observation no significant differences between these mechanical prostheses could be observed, however, after 14 years of long-term follow-up the cumulative event-free rates were more favorable for the BS prosthesis.
Improved Preparation of Soluble Dry Oxyhemoglobin Purified by Carbontetrachloride Treatment of Outdated Packed Erythrocytes
Authors: Přistoupil T.I. , Štěrbíková J.
Published: March 2018

A combination of treating outdated packed red blood cells (PRBCs) with carbontetrachloride, countercurrent dialysis and modified conditions of freeze-drying served to improve and standardize the technology of “stroma-free hemolysate” (SFH) in our laboratory. As a rule, proteins of the final product corresponded to 95% oxyhemoglobin, 3.5% methemoglobin and 1.5% non-hemoglobin ones. In freeze-dried samples stabilized with 0.24 molar saccharides, the weight proportions were 56% hemoglobin, 44% sucrose and/or 62% hemoglobin, and 38% fructose, respectively. If necessary, the saccharides could be rapidly removed from the easily reconstitued SFH by dialysis or chromatography. Analytical parameters were similar to those of chloroform-treated SFH stored dry at −12° C for 4 months. However, the present procedure was easier and SFH samples remained unchanged after dry storage even at +4° C for at least 13 months. This oxyhemoglobin product seems suitable for organ perfusion, further chemical modification and as an analytical standard.
Peptidyl Antithrombogenic Agents for Extracorporeal Blood Circulation
Authors: Ito S. , Matsuda T. , Takemoto Y. , Yamamoto K. , Kishimoto T. , Maekawa M.
Published: March 2018

The reduction of platelet aggregation and adhesion is essential for preventing thrombus formation during extracorporeal circulation. This report addresses some performances of peptidyl antithrombogenic agents which bind to the adhesive site of fibrinogen. This was based on the recent finding that the sequence of the binding domain of the platelet membrane receptor to fibrinogen was identified as TDVNGDGRHDL (one-letter amino acid code; Thr-Asp-Val-Asn-Gly-Asp-Gly-Arg-His-Asp-Leu), entitled B12. The addition of B12 and shorter-chain analogue peptides dose-dependently suppressed platelet aggregation and adhesion onto a fibrinogen-coated surface. The shorter the amino acid sequence, the less effective was inhibition. The inhibitory effect on platelet adhesion in vivo was significant under continuous infusion of B12. These inhibitory effects were compared with those by a receptor-binding RGD (Arg-Gly-Asp) peptide, which is the common active site to adhesive proteins.