bluuebunny/crossref_metadata_2025 huggingface dataset:
Initial In Vitro Evaluation of a Pediatric Vortex‐Mixing Membrane Lung
Authors: Peacock J. A. , Bellhouse B. J. , Abel K. , Bellhouse E. L. , Bellhouse F. H. , Jeffree M. A. , Sykes M. K. , Gardaz J. P.
Published: November 2008

Abstract: A new design for a pediatric membrane lung is described in this paper. The lung consists of eight blood compartments, each having six U‐shaped blood channels, with microporous PTFE membranes supported on rigid plates in such a way that the membranes form furrowed blood channels. Two rolling diaphragm pumps are attached to the open ends of the U‐shaped blood channels; these pumps are operated in antiphase. Mean flow is provided by a roller pump placed at the inlet end of the membrane lung. Pulsatile blood flow within the blood channels produces successive vortex formation and ejection, leading to good blood mixing and high efficiency in gas transport. The design of the rolling diaphragm piston pumps ensures that the blood prime volume is low (280 ml), and the grouping of the pumps at one end of the oxygenator allows the driving mechanism to be simple and compact. The relatively wide blood channels (minimum width 0.5 mm) and vortex mixing make priming the membrane lung particularly easy. The membrane area is 0.39 m2. Preliminary performance testing of the pediatric membrane lung was undertaken by pumping blood around a circuit containing a roller pump, the membrane lung, and a bubble oxygenator (to adjust the blood gases at the inlet to the membrane lung). In five such experiments it was shown that the membrane lung transferred 80 ml O2/min and 120 ml CO2/min at a blood flow rate of 1.5 L/min.
Failure of Hemodialysis to Diminish Psychotic Behavior in Schizophrenia: Behavioral and Psychophysiological Evaluation
Authors: van Kammen Daniel P. , Schulz S. Charles , Balow James E. , Zahn Theodore P. , Mundinger Gerhard , Flye M. Wayne , Bunney William E.
Published: November 2008

Abstract: In a double‐blind sham replacement study, eight drug‐free schizophrenic patients underwent 10 active and 10 sham hemodialyses for 20 weeks. At the end of the 10 active dialyses, none of the patients appeared to be improved in psychotic, affective, or social symptoms. Active dialysis was associated with a “startle“ response in heart rate and skin conductance to auditory stimuli, while sham dialysis was associated with an “orienting“ response. Night‐recorded sleep electroencephalography was unaffected by active dialysis. Spinal fluid beta‐endor‐phin‐like immunoreactivity levels were unchanged after active treatment. The behavioral improvements Reported in other studies may be related to “stress,“ psychotherapeutic support, spontaneous remissions, neuroleptic withdrawal, denial of symptoms, or diagnostic differences. This study did not confirm the claims for hemodialysis as a specific therapeutic intervention in schizophrenia.
Evaluation of Membranes for Plasmapheresis
Authors: Friedman Leonard I. , Hardwick R. A. , Daniels Julianne R. , Stromberg Robert R. , Ciarkowski Arthur A.
Published: November 2008

Abstract: Commercial flat‐sheet microporous membranes were evaluated for potential use in plasmapheresis with a specially designed filtration module. Significant differences in filtration rates were observed with different membranes. Saline filtration data were not useful in predicting the capacity of the membranes to filter plasma from whole blood. For all membranes studied, no rejection of plasma proteins was detected. No activation or deactivation of clotting factors was detected as a result of filtration. In addition, little or no hemolysis was caused by filtration with the various membranes. Saline, cell‐free plasma, platelet‐poor plasma, and whole blood were perfused over a track‐etched membrane and the resulting filtration rates were compared. The cell‐free plasma filtration rate decreased significantly with time, probably owing primarily to protein adsorption in the membrane pores. Cell‐free plasma and saline filtration data were used to calculate an apparent adsorbed layer thickness in the membrane pores. Perfusion of platelet‐poor plasma and whole blood resulted in time‐dependent filtration rates that were much lower than those obtained when cell‐free plasma was perfused. Results of the study support recent theoretical models that postulate that the ratelimiting process for blood filtration is the formation of a layer of blood cells (particle polarization) on the membrane surface.
Blood‐Dialyzer Interactions: Hemodynamic Manifestations in an Animal Model
Authors: Walker J. Frank , Lindsay Robert M. , Sibbald William J. , Linton Adam L.
Published: November 2008

Abstract: A sheep model is described that reliably produces acute pulmonary hypertension after blood, previously in contact with a number of different dialysis membranes including Cuprophan, enters the animal's circulation. This hemodynamic manifestation is associated with myocardial ischemia and arrhythmias and coincides in time with neutropenia but precedes maximal hypoxemia. The resulting pulmonary vascular response occurs following both exposure of flowing blood to a dialyzer in an extracorporeal circuit and reinjection of blood previously in static contact with a number of different devices for varying periods of time. Increasing volumes (1–15 ml) previously in static contact (10 min) with regenerated cellulose, saponified cellulose ester, and Cuprophan (hollow fiber and sheet form) caused varying increments in mean pulmonary artery pressure. Contact with either polyacrylonitrile or cellulose acetate resulted in little response. This effect was magnified with all the surfaces, even polyacrylonitrile and cellulose acetate, by prolonging the duration of contact up to 30 min. The hemodynamic events that occurred with this model are similar to those Reported in the clinical entity of “dialyzer hypersensitivity.“ This model may be of value in the quest for elucidation of the mechanisms involved in this syndrome.
The Current Status and Future of the Artificial Kidney
Authors: Funck‐Brentano J.‐L.
Published: November 2008

Abstract: The use of the artificial kidney can presently be extended to almost all patients with end‐stage renal failure. To reduce the cost of treatment, technological choices have to be made. These are always a compromise between cost and adequacy. The liberty obtained by technical improvements to perform a dialysis “à la carte,” depending on patient and doctor wishes, is one of the main characteristics of the present status of hemodialysis.
Metal Wear in Lillehei‐Kaster Heart Valve Prostheses
Authors: Silver Malcolm D. , Koppenhoefer Hannah , Heggtveit H. Alexander , Reif Thomas H.
Published: November 2008

Abstract: Ten Lillehei‐Kaster heart valve prostheses, in situ for up to 10 years and recovered at surgery or necropsy, were examined by light and scanning electron microscopy. All showed metal wear on the luminal aspect of their struts. The volume of wear related to the duration a prosthesis had been in situ. The worn metal showed distinct, transverse surface corrugations, which became more obvious with time. Aortic prostheses wore more and faster than mitral ones. One strut usually showed more wear than the other, a change likely due to specific manufacturing methods. It is believed that the pattern of wear is caused by a velocity‐controlled stick‐slip abrasive wear process, resulting from an interaction between the edge of the moving pyrolytic carbon disc, the struts' titanium surface, and the protein coat covering that surface. None of the patients had prosthesis dysfunction attributable to metal wear. Disc escape seems unlikely considering the degree of wear observed after 10 years. Furthermore, the surface corrugations did not appear to cause disc sticking or other problems. However, clinicians might consider monitoring patients who have borne these prostheses for >10 years.
Artificial Liver: Present and Future
Authors: Hori Motokazu
Published: November 2008

Abstract: Early in 1956, the first model of a biological artificial liver, using a live dog's liver incorporated in a cross‐hemodialyzer, was placed in an experimental animal with portocaval encephalopathy. This “biological artificial liver,” a hybrid artificial liver in the present terminology, was the first in the world. In October 1958, the first human patient, a young male patient in hepatic coma due to liver cirrhosis, was placed on the laboratory‐made biological artificial liver composed of four parabiotic cross‐hemodialyzers connected with four live dogs' livers to which the “hepatic reactors” for ammonium adsorption and acid‐base balance were additionally equipped. This first case was very successful, resulting in the patient's recovery from coma. This article introduces the past history of the artificial liver, research of which has mainly been conducted in Japan since the early 1950s by the author, M. Mito, and Y. Nosé. Until recently, little progress had been made in this field through the application of blood purification principles such as hemoadsorption, plasmapheresis, and other modifications and combinations. Accumulation of clinical experiences with such conventional methods has stimulated the third generation of the artificial liver to a return to a hybrid organ applying modern science and technology. A concept of hybrid organs in comparison with organ transplants is introduced. The Japanese national project of developing a new artificial liver system, as conducted by the author as the chairman and his associates, is introduced.
Development of Autonomous Paracorporeal and Implanted Artificial Heart and Circulatory Assist Systems
Authors: Shumakov V. I. , Kiselev Iu. M. , Tolpekin V. E. , Makeev A. N. , Razgulov M. M. , Vasin S. L.
Published: November 2008

Abstract: The development of autonomous systems for the artificial heart (AH) and for circulatory assistance (CA) has taken several directions. Studies relating to one direction—the development of paracorporeal and implanted systems based on thermal or electric motors—have been conducted at our institute in two stages, moving from stationary systems to totally implanted systems for long‐term use. The development of these systems is described. Improvements in the linear solenoid motor, used in some of the first paracorporeal systems, enabled progress toward the development of implanted CA systems based on a reversing electrohydraulic actuator. Modifications were also made in the control system. Early animal testing of these systems indicated that they could be effective in unburdening the heart cavities during left and right bypasses. Full implantation, however, demanded that the devices have improved forms and dimensions and less weight. Smaller electromechanical systems are being developed, and we are experimenting with ways to increase the overall autonomy of the system. An orthotopic model of an implanted AH is promising. Experiments continue on the use of the body's own skeletal muscles to create a blood pump.
Eosinophilia in Hemodialysis Patients
Authors: Friedberg Michael , Joffe Preben , Nielsen Bent , Nielsen Lars P.
Published: November 2008

Abstract: Thirteen percent of 99 patients undergoing maintenance hemodialysis showed an increased predialysis peripheral blood eosinophil count (mean value of 828 cells/mm3, range 410–2, 710). Patients with eosinophilia were predominantly male and evidenced more frequent elevation of total plasma IgE levels. Otherwise, no differences were found between patients with and without eosinophilia.
Postoperative Cardiac Support with a Pulsatile Assist Pump: Techniques and Results
Authors: Pierce William S. , Rosenberg Gerson , Donachy James H. , Landis Donald L. , Weiss William , Hensley Frederick , Larach David
Published: November 2008

Abstract: Since 1980 this group has employed a pulsatile assist pump(s) in 23 patients. Postoperative survival was 39% (9/23). In this group, 16 patients have required left ventricular support; 9 have been weaned from the pump, and 7 have survived (44%). Three patients required right ventricular support, and two have survived (66%). Four patients required biventricular assistance, but none survived. There have been four late deaths in this group. Of the five patients alive and well, all are New York Heart Association Class I or II. Important conclusions include the following: (a) The pulsatile pump can adequately support the pulmonary or systemic circulation for a period of days; (b) dramatic improvement in ventricular function is frequently observed in patients with univentricular failure; (c) adequate right ventricular function is a major determinant of survival in a patient with pulsatile left ventricular support; (d) preoperative cardiogenic shock and/or a prolonged time on cardiopulmonary bypass (CPB) predispose the patient to diffuse intravascular coagulation and a poor result; (e) considerable information remains to be learned regarding the selection of assist pump candidates, optimal CPB techniques, and intraop‐erative identification of biventricular failure, which will further improve these results.
Combining Novel Biomolecules and Stimuli‐Sensitive Biomaterials into New Recognition‐Response Biomaterial Systems
Authors: Hoffman Allan S.
Published: November 2008

Abstract: : An important present and emerging trend in biomaterials development is the synthesis of polymers which combine capabilities of biologic recognition (“biomimetic”) with sensitivity to small environmental changes (“stimuli‐responsive”). This short article highlights some of the many opportunities and challenges in this exciting area.
Reduction in Platelet‐Binding Immunoglobulins and Improvement in Platelet Counts in Patients with HIV‐Associated Idiopathic Thrombocytopenia Purpura (ITP) Following Extracorporeal Immunoadsorption of Plasma Over Staphylococcal Protein A‐Silica
Authors: Snyder H. W. , Bertram J. H. , Channel M. , Ernst N. R. , Jones F. R. , Balint J. P.
Published: November 2008

Abstract: Platelet‐directed antibodies and circulating immune complexes (CIC) were removed from plasma of patients with human immunodeficiency virus (HIV) infection and idiopathic thrombocytopenic purpura (ITP) by extracorporeal immunoadsorption using columns of Staphylococcal protein A‐silica (Prosorba columns). In addition, stimulation of a broadly cross‐reactive anti‐F(ab́)2 antibody response was observed. These antibodies also appeared to play a role in the additional removal of platelet‐directed immunoglobulins (Igs) and CIC from plasma. Removal of these components from plasma was associated with diminishing levels of antibodies and CIC on patient platelets and significant increases in platelet counts. Extracorporeal immunoadsorption of IgG and CIC from plasma is a beneficial new treatment modality for HIV‐associated ITP.
Electrical Pulse Train and Single Pulse Stimulation of the Small Intestine: Acute and Chronic Studies in the Dog
Authors: Moritz Anton , Grundfest‐Broniatowski Sharon , Ilyes Laszlo , Kasick Jerry , Jacobs Gordon , Olsen Eric , Nosé Yukihiko
Published: November 2008

Abstract: In vitro tests have shown that electric currents may lead either to relaxation or contraction of the bowel wall. Because voluntary changes of the intestinal motility could be useful in the treatment of intestinal disorders, we investigated the reactions elicited by electrostimulation of the small intestine in the intact animal. Stimulating electrodes, electroenteromyogram electrodes, and pressure monitoring tubes were used to instrument a 5‐cm segment of the proximal jejunum in five dogs in acute studies and in two dogs in chronic studies. Single pulses of 200 ms elicited a pulsatile pressure increase of 10‐35 mm Hg. Pulse train stimulation was followed by a more complex reaction. Trains of 500‐μs, 910‐Hz pulses at 30 mA evoked a 50‐80 mm Hg pressure increase, 1‐ms, 10‐Hz trains caused an initial relaxation, followed by a pressure increase during stimulation and a further pressure increase after termination of the burst. These reactions were similar to those observed by Campbell working with colon in vitro. The chronic fasted animals reacted to 500μs, 910‐Hz, 25‐mA stimulation with a mean pressure increase of 26 mm Hg (n=10) and to 200‐μs; 1.67‐kHz, 30 mA stimulation with 28 mm Hg (n=16). In the fasted animals a pressure increase during stimulation predominated (Campbell type I), whereas in the fed animal an additional off response after termination of the stimulation was the most common type of reaction (Campbell type II). Initial relaxation (Campbell type III) could be elicited by 1‐ms, 10‐Hz trains. In summary, contraction patterns similar to those observed in vitro can be achieved in anesthetized and awake animals with currents tolerated by the trained dog.
Endothelial Cell Seeding on Different Polyurethanes
Authors: Gerlach J. , Schauwecker H. H. , Hennig E. , Bücherl E. S.
Published: November 2008

Abstract: Six polyurethanes (PUs) were tested with respect to their cytocompatibility. Initial adhesion, initial spreading, and the proliferation of endothelial cells were investigated. All smooth PUs showed similar initial adhesion. Initial spreading was faster on rough PUs. Collagen coating resulted in faster initial adhesion but not better proliferation of endothelial cells.
Plasma Separator for Encapsulating Fluorescent Probe in Erythrocytes
Authors: El‐Kalay M. A. , Abdel‐Kader M. H. , Hamzah R. Y. , Al‐Shirbini S. A.
Published: November 2008

Abstract: Using a plasma separator, it is possible to wash large volumes of whole blood free of plasma proteins in short periods. The novelty, however, is that the same apparatus can be used to reversibly hemolyze and reseal the red blood cells (RBCs) using hypotonic and hypertonic dialysates, respectively. This technique was assessed using the fluorescent exogenous agent uranin (flu‐orescein sodium). Results indicate that the encapsulation of the RBCs can be completed in under 2 h. The encapsulation efficiency of the RBCs was approximately 80% with a RBC recovery rate of 75%.
Hemodynamic Parameters Influencing Clinical Performance of Novacor Left Ventricular Assist System
Authors: Miyamoto Yuji , Kormos Robert L. , Borovetz Harvey S. , Gaisor Thomas , Pristas John M. , Armitage John M. , Hardesty Robert L. , Griffith Bartley P.
Published: November 2008

Abstract: The interrelationships between hemodynamic variables including right ventricular (RV) performance with filling/ejection dynamics of the Novacor left ventricular assist system (LVAS) were determined in 10 of 11 patients who received LVAS as a bridge to heart transplant. Nine were successfully transplanted. Data were obtained intraoperatively, at periodic intervals up to 48 h postimplant and at explant. The hypotheses investigated included (a) RV performance influences LVAS filling characteristics and (b) LVAS pump output is influenced by systemic vascular resistance (SVR). During the period of LVAS support (2–126 days), pumping characteristics included a mean filling volume of 51 ml (range, 24–70), residual volume of 4.9 ml (range, 1–18), pump rate of 113/min (range, 63–175), and pump output of 5.81/min (range, 2.8‐8.2). Multiple regression analysis identified pulmonary vascular resistance (PVR), RV stroke work index (RVSWI), and pulmonary capillary wedge pressure, but not RV ejection fraction, pulmonary artery pressure, or central venous pressure (CVP) as the most important correlates with LVAS filling volume (p < 0.001, R2 = 0.6). In addition, LVAS pump output was influenced mainly by RVSWI, PVR, and SVR (p < 0.001, R2 = 0.7). It was concluded that LVAS performance is highly dependent on RV function and systemic/pulmonary vascular resistances.
Postganglionic Sympathetic Nerve Activity with Correlation to Heart Rhythm During Left Ventricular Assistance
Authors: Yambe Tomoyuki , Nitta Shin–ichi , Katahira Yoshiaki , Sonobe Taroh , Naganuma Shigeru , Akiho Hiroshi , Chiba Shigeki , Kakinuma Yoshito , Hayashi Hiroyuki , Tanaka Motonao , Miura Makoto , Satoh Naoshi , Mohri Hitoshi , Yoshizawa Makoto , Takeda Hiroshi
Published: November 2008

Abstract: In order to evaluate the effect of ventricular assist device (VAD) driving on the autonomic nervous system, sympathetic neurograms during left ventricular (LV) assistance were analyzed by power spectrum and coherence function. Our TH–7B pneumatically–driven sac–type VAD was used in seven adult mongrel dogs. VADs were inserted between the left atrium and the descending aorta. Renal sympathetic nerve activity (RSN A) was detected by use of bipolar electrodes attached to the left renal sympathetic nerve via a retroperitoneal approach. Values of squared coherence between the arterial, pulse wave and RSNA were measured at the same frequency of cardiac and VAD pumping rhythms. During LV assistance, coherence at the cardiac rhythm frequency was decreased, and coherence at the VAD pumping rhythm frequency was increased. These results indicate that the arterial pulse wave, which was produced by the VAD assistance, contributed to postganglionic sympathetic nerve activity.
Accidental Metabolic Acidosis during Hemodialysis
Authors: Hartmann Anders , Reisœter Anna , Holdaas Hallvard , Rolfsen Børge , Fauchald Per
Published: November 2008

Abstract: Three incidents of metabolic acidosis during hemodialysis in 3 different patients are presented. Two patients became severely ill but recovered completely after treatment. In the third patient, the event was recognized before the acidosis became symptomatic. In all cases the acidosis was caused by an unbalanced supply of acidic dialysis concentrate. Two events were caused by mistaking acidic dialysis concentrate for acetate. In the third patient, the supply line from the bicarbonate concentrate jug was broken. The conductivity cell alarm was not activated during any of the incidents and in only 1 case during reconstruction of the accidents. The efficacy and safety of the conductivity cell alarm system regarding prevention of acid/base disturbances during hemodialysis are discussed.
A New Pectin‐Based Material for Selective LDL‐Cholesterol Removal
Authors: Iewińska Dorota , Rosiński Stefan , Pia̧tkiewicz Wojciech
Published: November 2008

Abstract: A new material, natural polysaccharide‐pectin, was tested for removal of human blood lipoproteins. Pectin was prepared in a granular form with the help of the specifically designed gelification device and tested in batch sorption experiments in vitro for removal of total cholesterol (TC), LDL‐cholesterol (LDL‐C), and HDL‐cholesterol (HDL‐C) from human plasma. Pectin granules removed 40% of TC, 45% of LDL‐C, and 36% of HDL‐C on average with respect to the initial amounts whereas corresponding values for LA‐40 Kanegafuchi adsorbent were 69%, 81%, and 33% in the same experimental conditions (shaking 1 g of sorbent sample with 2 ml of plasma).
Frequency of Seal Disruption with the Sarns Centrifugal Pump in Postcardiotomy Circulatory Assist
Authors: Curtis Jack J. , Boley Theresa M. , Walls Joseph T. , Demmy Todd L. , Schmaltz Richard A.
Published: November 2008

Abstract: We have used the Sarns centrifugal pump for uni‐ or biventricular assist in 58 patients with postcardiotomy cardiogenic shock. This device utilizes a spinning impeller pump that is magnetically coupled to a motor imparting rotary motion to incoming perfusate. Nine patients (16%) experienced 22 device failures, which consisted of a nonvisible disruption of the seal within the pumphead. This allowed fluid to accumulate between the pumphead and the motor necessitating change of the pumphead. The time to seal disruption was 10–149 h (median 48). Of the 22 seal disruptions, 18 occurred in 73 left ventricular pumps (25%), and 4 occurred in 38 right ventricular pumps (11%) p = 0.015. Left ventricular pumps failed at 10–144 h (median 48), and right ventricular pumps failed at 48–149 h (median 83) p = 0.02. The Sarns centrifugal pump is dependable for its intended use of cardiopulmonary perfusion. However, when used for postcardiotomy assist, seal disruption should be expected. It occurs sooner and is more common during left ventricular assist. We recommend inspection of the magnet chamber for evidence of seal disruption every 12 h with left ventricular assist and every 24 h with right ventricular assist.
New Processes for Surface Treatment of Catheters
Authors: Sioshansi Piran
Published: November 2008

Abstract: Infection, thrombosis, and stenosis are among the most common complications of blood‐contacting catheters and are caused by surface properties of the substrate materials. Ion beam‐based processes such as ion implantation and ion beam‐assisted deposition affect only the outer micron of the treated material surface; there is little effect on bulk properties. These processes were therefore used on common catheter materials, and their biological properties were evaluated. Ion implantation of materials such as silicone rubber resulted in a less tacky, more wettable surface that demonstrated thrombusresistance in both in vivo and preliminary clinical studies. Ion beam‐assisted deposition was used to deposit silverbased coatings, which demonstrated antimicrobial activity in in vitro and clinical studies. Biocompatibility of these processed catheter materials was also demonstrated using simple laboratory studies. These processes, therefore, can be readily applied to blood‐contacting catheters to make them thrombus‐ and infection‐resistant.
A Treatment System for Implementing an Extracorporeal Liver Assist Device
Authors: Gislason Gardar T. , Lobdell Donn D. , Kelly James H. , Sussman Norman L.
Published: November 2008

Abstract: Biologically active devices are receiving increasing attention, especially in the management of endocrine pancreatic failure (diabetes) and acute liver failure. In both instances, mechanical devices have been unable to replace the function of the original organ, and consequences range from inconvenient (e.g., regular insulin shots, diabetic vasculopathy) to fatal (e.g., fulminant hepatic failure). In developing a cell‐based liver assist device, we concluded that currently available extracorporeal blood treatment systems are not suited to the delivery of high molecular weight substances and that they do not adequately address the metabolic needs of the device. We therefore developed a system that provides safe, continuous perfusion of an extracorporeal organ. We detail the design and first clinical use of the system.
In Vitro Evaluation of the Influence of Pulsatile Intraventricular Pumping on Ventricular Pressure Patterns
Authors: RAKHORST GERHARD , VERKERKE GIJSBERTUS J. , HENSENS AB G. , De MUINCK EBO D. , BLANKSMA PAUL K. , PILLON MASSIMO , JUFER MARCEL
Published: November 2008

Abstract: The Pulsatile catheter (PUCA) pump consists of a single port membrane pump connected to an indwelling valved catheter. This so–called transarterial blood pump was originally designed to be introduced through a superficial artery into the left ventricular cavity to pump blood from the left ventricle into the ascending aorta. By introducing the catheter directly into the thoracic aorta or the pulmonary artery, the possibility is created of applying large–diameter catheter PUCA pumps as left, right, or biventricular assist devices (LVAD, RVAD, or BIVAD) without damaging any of the structures of the heart. The pump performance of an 8 mm PUCA pump prototype (internal diameter catheter, 8 mm; catheter length, 40 cm; stroke volume, 80 ml) was studied in a mock circulation to investigate the influence of pulsatile intraventricular pumping on ventricular pressure patterns. The pumping mode of the PUCA pump was changed from approximately 1: 1 ([n + l]: n) to 1: 2 ([1/2n + l]: n) and 1: 3 ([1/3n + l]: n) in relation to the frequency of a ventricle–simulating membrane pump. Apart from the pumping mode, timing of the PUCA pump driving system (ejection phase) seems to be crucial in obtaining optimal unloading of the ventricle.
Hemoperfusion during Coronary Angioplasty: First European Experience with a New Hemoperfusion Pump
Authors: De MUINCK EBO D. , MEEDER JOAN , MAGIELSE CHRISTEL , BOM VICTOR J. J. , Van DIJK RENÉ B. , VERKERKE GIJSBERTUS J. , LIE KONG I.
Published: November 2008

Abstract: Hemolysis tests with fresh human blood were performed in vitro with a new 5 ml, piston–type hemoperfusion pump, designed to prevent myocardial ischemia during coronary angioplasty. Despite driving pressures greater than 3 atmospheres, shear stress greater than 200 Pa, turbulent pump flow, and the presence of occlusive valves, hemolysis proved to be minimal. This effect is explained by the short amount of time that blood is subjected to mechanical forces that cause hemolysis in the system and by the small volumes of blood involved. During clinical application of the system, angina pectoris, electrocardiographic changes, and systemic blood pressure were used as parameters for myocardial ischemia. There was an effective reduction of ischemia during prolonged (10 min) balloon inflation, demonstrated by the absence of angina, minimal electrocardiographic changes, and normal blood pressure. In addition, the system proved to be safe and effective during high—risk angioplasty.
The Helmholtz Total Artificial Heart Labtype
Authors: KAUFMANN RALF , REUL HELMUT , RAU GUNTER
Published: November 2008

Abstract: To perform the first experimental tests for validation of a new gear unit concept, the pump chamber, diaphragm, and pusher plate design of an orthotopic electromechanical total artificial heart (TAH) (Helmholtz Labtype) was manufactured. In its early stage of development, it provides some of the most important features of the conceptual final artificial heart. The new gear unit transforms a uniform unidirectional rotational motor movement into translatory pusher plate movements, with resting phase in the end–diastolic position, and the angled pump chamber orientation determines the available space for the motor and gear unit. Furthermore, this labtype provides flexibility with regard to use of different types of structural parts for experimental investigations. The first in vitro test results, obtained with specially designed circulatory mockloops that simulate physiological preload and afterload conditions, are presented. They comprise pressure and flow generation, motor performance, efficiency, and energy consumption. The results prove the feasability of the new gear unit concept for an electromechanical artificial heart and allow a reliable determination of the necessary performance of the future brushless DC motor for the first in vivo TAH model.
Pulsatile Flow and Simple Flow Control Method During Weaning Period in Centrifugal Pump: Toward More Expanded Usage in Open Heart Surgery
Authors: Nishida Hiroshi , Koyanagi Hitoshi , Endo Masahiro , Suzuki Susumu , Oshiyama Hiroaki , Nojiri Chisato , Fukasawa Hiromichi , Akutsu Tetsuzo
Published: November 2008

Abstract: To expand the usage of the centrifugal pump (CP) in open heart surgery, we performed two studies. In the first, we evaluated pulsatile flow in the CP. In vitro pump performance of the Terumo Capiox pump (TCP) and the Sarns Delphin pump (SDP) and increase of free hemoglobin (mg/dl) after driving 6 h were investigated using bovine blood. A roller pump (RP) was used as a comparison. Equally effective pulsatile flow was obtained in both CPs. Hemolysis was less severe in TCP (120 mg/ dl) than SDP (210 mg/dl) and RP (320 mg/dl). In the second study, we evaluated a simple flow control method. Flow rate was easily controlled with step–wise clamping of 3–pronged tubing (Triple–flow) without changing rotational speed, regardless of afterload. Fluctuation of flow was much less with this method than with the rotational speed change method. The use of pulsatile flow of TCP, with its minimum increase of hemolysis and the easier flow control method during the weaning process, may expand the usage of CP in open heart surgery.
Clinical Evaluation of a New Type of Centrifugal Pump
Authors: Ninomiya J. , Shoji T. , Tanaka S. , Ikeshita M. , Ochi M. , Yamauchi S. , Yajima T. , Yamauchi H. , Sugimotox T. , Aizawa T.
Published: November 2008

Abstract: The major problems with existing centrifugal pumps are leakage, mechanical trauma, and thrombus formation. In consideration of these problems, a new compact centrifugal pump system was developed. The purpose of this study was to evaluate the new centrifugal pump system clinically. Ten patients underwent open heart surgery with a centrifugal pump or a roller pump. During surgery, hemodynamic and hematological data were obtained. A pulsatile assist device in the pump circuit was used in patients with severe heart disease. There was neither operative death nor hospital mortality, and there was no difference with regard to hemodynamic data between the two groups. The centrifugal pump group, however, had significantly lower hemolysis, especially during prolonged cardiopulmonary bypass. This centrifugal pump could also create sufficient pulsatile flow with a pulsatile assist device. Postoperative macroscopic and microscopic findings demonstrated the smooth surface of the pump without thrombus formation. This centrifugal pump system might be useful for prolonged cardiopulmonary bypass.
The Vicious Cycle of Nonhealing Neointima in Fabric Vascular Prostheses
Authors: Noishiki Yasuharu , Tomizawa Yasuko , Yamane Yoshihisa , Matsumoto Akihiko
Published: November 2008

Abstract: Delayed neointimal healing of a fabric vascular prosthesis was investigated in an animal study focusing on the relationship between red thrombus, fibrinolysis, and endothelialization on the luminal surface. Fabric vascular prostheses were implanted into the descending aortas of 72 dogs. Fifty‐nine grafts were explanted from 1 h to 1,705 days after implantation. One hour after implantation, the graft wall was red in color due to fresh thrombus; however, at 1 day the luminal surface became white. Red thrombus reappeared at 1 week and remained present in the long‐term. Microscopically the initial red thrombus contained numerous erythrocytes. The white thrombus at 1 day was composed of a dense fibrin network without erythrocytes. At 2 days numerous lacunae appeared in the fibrin layer, and at 3–5 days cavernae and low density fibrin areas were present secondary to fibrinolysis. These areas allowed the blood components to infiltrate into the fibrin layer, and as a result red thrombus reformed within it. The thrombi on the luminal surface in the long‐term was always red in color and composed of complicated, multiple stages of thrombus formation, i.e., fresh thrombus with erythrocytes, dense fibrin without erythrocytes, low fibrin density areas, lacunae and cavernae in the fibrin layer, and blood component infiltration into these spaces. Thrombus was always newly formed and present, and involuted in parallel due to fibrinolysis, suggesting that these phenomena perpetuated in a vicious cycle. However, at the anastomoses fibrinolysis was present, but blood component infiltration was prevented by the endothelial cell lining. These results suggest that endothelialization may arrest the vicious cycle of non‐healing neointima in fabric vascular prostheses.
New Concept of Microporous Structure in Small Diameter Vascular Prostheses
Authors: Okoshi Takafumi
Published: November 2008

Abstract: Six types of skinned and microporous vascular prostheses (1.5 mm ID) with different hydraulic permeabilities (HP) were fabricated with either a polyurethane polydimethylsiloxane (PU‐PDMS) or a polyvinylidene fluoride‐trifluoroethylene (PVDF‐TrFE) by the spray phase inversion technique: skinned PU‐PDMS grafts with an HP of 0 ml/min/cm2 (PU‐PDMS‐S‐0), microporous surfaced PU‐PDMS grafts with an HP of 2.7 ml/min/cm2 (PU‐PDMS‐2.7), microporous surfaced PU‐PDMS grafts with an HP of 39 ml/min/cm2 (PU‐PDMS‐39), poled skinned PVDF‐TrFE grafts with an HP of 0 ml/min/cm2(poled PVDF‐TrFE‐S‐0), poled microporous surfaced PVDF‐TrFE grafts with an HP of 41 ml/min/cm2 (poled PVDF‐TrFE‐41), and unpoled microporous surfaced PVDF‐TrFE grafts with an HP of 41 ml/min/cm2 (unpoled PVDF‐TrFE‐41). Straight segments of these grafts (1.5–2.2 cm in length) and one loop PU‐PDMS‐39 (10 cm in length) were implanted in the rat infrarenal aorta. Graft surface morphology and wall porosity as reflected by hydraulic permeability were the main determinants of early patency and completeness of healing including endothe‐lialization.
Late Results of Clinical Experience with Small Caliber Biological Grafts
Authors: Ninomiya Junichi , Tanaka Shigeo , Shoji Tasuku , Noishik Yasuharu
Published: November 2008

Abstract: Small caliber biological grafts that were hepa‐rinized and nonheparinized were implanted in 52 patients with arterial obstructive disease and chronic renal failure by either conventional suture anastomosis or laser anastomosis over the last 8 years. There were no operative mortalities. The overall postoperative patency rate was 91% at 1 year, 85% at 3 years, and 82% at 5 years. The heparinized graft anastomosed by laser clearly had the best results with a 100% patency rate at 5 years without pathological anastomotic intimal hyperplasia. Therefore, the heparinized biological graft anastomosed by laser could be the best option for the reconstruction of small vessels although these grafts might be clinically useful for small caliber grafts.
Clinical Use of Low Porosity Woven Ultrafine Polyester Fiber Grafts
Authors: Satoh Shinichi , Niu Satoshi , Kanda Keiichi , Hirai Jiro , Nakazima Syunsuke , Wada Yukio , Oka Takahiro , Noishiki Yasuharu
Published: November 2008

Abstract: A woven fabric graft made of ultrafine polyester fibers (UFPF) (Toray Graft, water porosity: 100 ml/ min/cm2:120 mm Hg H2O) was clinically applied in 81 cases (28 thoracic aortic aneurysms, 6 thoracoabdominal aortic aneurysms, 42 abdominal aortic aneurysms, and 5 atherosclerotic obstructions of the peripheral arteries). Eight patients died after surgery due to causes unrelated to the graft. The other 73 patients were in good condition after surgery. For operations requiring extracorporeal circulation, the graft was presealed with human albumin. For the abdominal aortic aneurysms, the graft was pre‐clotted in situ with nonheparinized autoblood after the completion of the proximal anastomosis. It took about 2 min to complete the preclotting. A nonsealed graft was used for the reconstruction of peripheral arteries for theintraaortic balloon pumping procedure. The graft was easy to handle. There was no cut edge fraying problem with the graft in any direction of cutting. Even after pre‐sealing, the graft was soft and pliable enough to enable easy adaptation and anastomosis. Just after implantation, bleeding was minimal from the graft wall, anastomotic sites, and suture pores, and it stopped spontaneously. These clinical data showed that the woven UFPF graft exhibited both easy handling despite in spite of low porosity and safe application in the reconstruction of arterial systems even under totally heparinized conditions during extracorporeal circulation.
The Inferior Vena Cava Diameter as a Marker of Dry Weight in Chronic Hemodialyzed Patients
Authors: Ando Yasuhiro , Yanagiba Satoru , Asano Yasushi
Published: November 2008

Abstract. We have previously reported that the diameter of the inferior vena cava (IVC) reflects the amount of body fluid in hemodialyzed (HD) patients. The present study was undertaken to depict the criteria of IVC diameters for determining dry weight (DW) in anuric HD patients. In healthy subjects, the maximal diameters during quiet expiration (IVCe) and the minimal diameters during quiet inspiration (IVCi) were 16.7 ± 3.2 and 5.7 ± 5.4 mm, respectively (mean ± SD). The collapsibility index (CI, 1 – IVCi/IVCe), which inversely correlates with the central venous pressure, was 0.68 ± 0.29. In anuric HD patients, the IVCe/CI values before and after HD were 14.9 ± 3.2/0.68 ± 0.24 and 8.2 ± 2.3/0.94 ± 0.09, respectively. IVCe decreased proportionally to the amount of ultrafiltration. In HD patients with hypervolemic pulmonary edema, the IVCe and CI values were 22.4 ± 2.9 and 0.22 ± 0.11, respectively. We proposed that IVCe/CI after HD is 8 ± 3 mm/0.9 ± 0.1 as the markers of DW in anuric HD patients and that an IVCe value ≥22 mm together with a CI ≤0.22 implies the warning level of body fluid retention.
A Fluid Dynamic Analysis Using Flow Visualization of the Baylor/NASA Implantable Axial Flow Blood Pump for Design Improvement
Authors: Wernicke Jens‐Thomas , Meier Dirk , Mizuguchi Kazumi , Damm George , Aber Greg , Benkowski Robert , Nose Yukihiko , Noon George P. , DeBakey Michael E.
Published: November 2008

Abstract: The Baylor/NASA Axial Blood Flow Pump has been developed for use as an implantable left ventricular assist device (LVAD). The pump is intended as an assist device for either pulmonary or systemic circulatory support for more than 3‐months' duration. To date the pump provides acceptable results in terms of thrombus formation and hemolysis (IH of 0.018 g/100 L). A fluid dynamics analysis using flow visualization was performed to investigate the flow fields and to determine areas within the pump that could be improved. These studies focused upon the inflow area in front of the pump. A prototype axial flow pump assembly was constructed to facilitate the flow visualization studies. Particle image tracking velocimetry techniques were used to measure Amberlite particles suspended in a blood analog fluid composed of 63% water and 37% glycerin. This method used a pulsed (612 Hz) laser light to determine flow velocity profiles, shear stress, Reynolds numbers, and stagnant areas within the axial pump. These studies showed that the flow straightener (a vaned assembly in the pump inflow) reduced Reynolds numbers from 4,640 to 2,540 (at 8.5 L/min) and that the flow straightener exacerbates a discontinuity found between it and the impeller. Within the inflow area, a maximum of 80 N/m2 shear stress was measured, which is well below published blood damage thresholds. Design variations were investigated resulting in a smoother flow transition between flow straightener and impeller. These variations must be investigated further to establish a correlation with hemolysis and thrombus formation.
Study on Sodium and Potassium Balance During Hemodialysis
Authors: Kotyk P. , Lopot F. , Czech J. Bláha
Published: November 2008

It is the goal of this section to publish material that provides information regarding specific issues, aspects of artificial organ application, approach, philosophy, suggestions, and/or thoughts for the future.

Abstract: To acquire data for adequate ultrafiltration (UF) control, sodium and potassium balance was investigated during hemodialysis (HD) in 16 hemodialyzed patients. Overall balances were evaluated from concentration measurements of the in‐ and outflowing dialysate and pre‐ and postdialysis plasma. The diffusive and convective part of the electrolyte removal and its intra‐ and extracellular space (ICS, ECS) component were calculated. During a 5‐h HD, 40–110 mmol of potassium is removed, predominantly by diffusion (72–88%). Calculation shows that 40–70% of the removed amount is taken from the ICS. Sodium's overall HD showed much higher scatter, ranging from positive values to 500 mmol removal. The diffusive component was positive in most cases. By ultrafiltration sodium is removed in all cases. Calculations also showed in all cases that sodium was delivered to the ICS. This is in contradiction with the general belief that exchangeable sodium is distributed solely in ECS (1,2,6,7). This may be a sign of the effort to keep changes of ICS osmotic load at a minimum. Based on the finding of the exchange of sodium for potassium in the cellular wall, a method has been devised to calculate the UF fraction removed from EC (UFEC) expressed as a coefficient KEC=UFEC/UFToT, with UFToT being the total fluid volume removed during the HD session.
Congress Presidential Address: 5th WAA Congress Therapeutic Artificial Organs, 10 Years After
Authors: Nosé Yukihiko
Published: November 2008

Abstract: In 1983, more than 10 years ago, the concept of therapeutic artificial organs was proposed by this author. Currently developments of various types of immunomod‐ulation technologies are well established, and therapeutic artificial organs for the treatment of autoimmunodiseases have become a well‐accepted concept. It is this author's opinion that if we utilize apheresis technologies properly we should be able to prevent the aging process of mankind. Physical youth, and perhaps mental youth, can be achieved by apheresis technologies. However, in order to maintain youth and enjoy a high quality of life, it is essential to maintain a strong will to live. In this paper a new type of an artificial organ is proposed. This antiaging artificial organ is named “Juzo,” the organ for a longer life, in Japanese, by this author.
A Feasibility Study on a New Artificial Sphincterfor Colostomy
Authors: de Paula Josuê Bruginski , Cliquet Alberto
Published: November 2008

Abstract: Although many efforts have been put forth, fecal incontinence of colostomates is still an unsolved problem. Among the techniques available to improve continence, the use of electromagnetic/mechanical power has not been explored. Our work looks at the characteristics needed by the components of an artificial sphincter where the power of sphincteric muscles is substituted with electromagnetic/mechanical power, and the mechanical absence of muscles is replaced by a plastic band. Experimental work was done with isolated colon of 26 mongrel dogs, and all of them became continent by an intralumi‐nal gas pressure over 80 mm Hg when a final perimeter between 3.7 and 4.7 cm was reached. No macroscopic lesions were noted on the guts' surface beneath the plastic band. The largest band displacement was 4.2 cm, and the traction force was under 50 N.
Hemodialysis Versus Continuous Ambulatory Peritoneal Dialysis: Effects on the Heart
Authors: Canziani M.E. , Neto M. Cendoroglo , Saragoça M.A. , Cassiolato J.L. , Ramos O.L. , Ajzen H. , Draibe S.A.
Published: November 2008

Abstract: In this study we compared the influence of 2 different modalities of treatment, CAPD and hemodialysis, on the prevalence and severity of left ventricular hypertrophy and cardiac arrhythmias of chronic renal failure patients. We compared 27 patients on the CAPD program with 27 patients on to chronic hemodialysis matched for sex, age, and duration of dialysis treatment. The prevalence of hypertension was significantly lower in CAPD than in hemodialysis patients (41% vs. 81%, p = 0.0023). Blood pressure levels were also lower in CAPD than in hemodialysis patients (systolic pressure 124.9 ± 4.7 vs. 154.8 ± 4.6 mm Hg, p < 0.0001; diastolic pressure 77.5 ± 2.9 vs. 93.3 ± 2.8 mm Hg, p =0.0001). Left ventricular hypertrophy (LVH) was present in 52% of CAPD and in 93% of hemodialysis patients(p =0.0008).Severe cardiac arrhythmias (Lown 3–4) occurred in only 4% of CAPD and in 33% of the hemodialysis group(p =0.0149).The lower frequency of LVH in CAPD might explain the lower incidence of severe arrhythmias.