bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of High Pressure on Microporous Membrane Oxygenator Failure
Authors: Tamari Yehuda , Tortolani Anthony J. , Maquine Melanie , Lee–Sensiba Kerri , Guarino John
Published: July 2010

Abstract: A retrospective study to determine the relationship between early microporous membrane oxygenator (MMO) failure and blood pressure at the MMO outlet (Pmo) conducted using data collected with 19 dogs (22 ± 1 kg, mean ± SEM) undergoing routine normothermic cardiopulmonary bypass. Because gas flow was maintained at a high level, it could not be used to control C02 exchange. Instead, blood Pco2 was controlled by adding C02 to the sweep gas. Blood Po2 was controlled as suggested by the manufacturer, by adjusting the %O2 in the gas phase (g). Blood flow was 2575 ± 54 ml/min; Pmoranged from 173 to 790 mm Hg; and hematocrit was 33 ± 1%. O2 exchange was calculated from blood gas parameters. Changes in the diffusion potential of O2 (APo2) and CO2 (APco2) and MMO performance (P, taken as oxygen exchange normalized to a diffusion potential of 100 mm Hg) indicated MMO failure. Initial values, taken within 60 min of bypass initiation, were compared to final values taken at 226 ± 9 min of bypass. Despite higher final APo2 (411 ± 9 vs. 538 ± 19 mm Hg, p < 0.0001 paired t–test) and APco2 (18.6 ± 2.4 vs. 30.5 ± 4.7 mm Hg, p < 0.0017), arterial blood Po2 decreased (159 ± 15 to 89 ± 6 mm Hg, p < 0.0005) and Pco2 increased (36.4 ± 1.5 to 46.1 ± 3.0 mm Hg, p < 0.0039), and the performance decreased [24.5 ± 1.1 to 20.1 ± 0.7 (ml/min)/(100 mm Hg), p < 0.0001]. Regression analysis of variance between the difference in initial (I) and final (F) values and MMO outlet pressure showed that APco2(F –I) = 0.051 pmo–3.2 (r= 0.75) and δPo2= 0.378Pmo– 11.0 (r= 0.93). Final performance as a percentage of initial performance was related to Pmo by P (%) = 98 – 0.0541Pmo(r= 0.87). MMO failure was observed within 3 h and was usually associated with ultrafiltrate expelled from the MMO gas exhaust port. Failure was most likely due to plasma breakthrough and was not prevented by high sweep gas flow. MMO failure was not correlated with time on cardiopulmonary bypass, probably due to the large number of variables in the study. Key Words: Oxygenator–Microporous membrane failure–Plasma breakthrough–Pressure.
Thoughts and Progress
Authors: Funakubo Akio , Sakuma Ichiro , Fukui Yasuhiro , Kawamura Tsuyoshi
Published: July 2010

Abstract: In recent years, extracorporeal membrane oxygenation (ECMO) has been used for treatment of neonates with respiratory failure. A prototype of a compact ECMO system for neonates was developed. A single–lumen catheter, inserted into the right atrium via a jugular vein, was used for withdrawal and infusion of blood through the catheter. An extracapillary flow hollow–fiber membrane lung made of microporous polypropylene has a total surface area of 0.6 m2. To prevent the increase of plasma free hemoglobin, the ratio of withdrawal/infusion is controlled by a microcomputer. The system is compact in size with a low priming volume (<90 ml), which allows for ECMO with no additional blood transfusions. Its potential application as a respiratory support system is evaluated in animal experiments. The total intermittent venoveno bypass flow was 15 –30 ml/min/kg. The O2 transfer rate was 20 ml/min and the CO2 transfer rate was 33 ml/ min at a blood flow rate of 300 ml/min. The O2 and CO2exchange with the ECMO system was efficient enough to eliminate the respiratory failure induced by mechanical ventilation. The increase in plasma free hemoglobin was only 4 mg/dl after 6 h of ECMO. The system was considered applicable to respiratory aid for neonates.
Immunosorbent for Selective Removal of Lipoprotein (a) from Human Plasma: In Vitro Study
Authors: Pokrovsky Sergei N. , Adamova Irina Yu. , Afanasieva Olga Y.
Published: July 2010

Abstract: Sheep polyclonal anti–lipoprotein (a) [anti–Lp(a)] antibodies were used for immunosorbent preparation. The ability of the selective removal of Lp(a) from human plasma by this sorbent was demonstrated in an in vitro study. The material desorbated from the anti–Lp(a) column by acid pH has immunochemical properties identical to those of Lp(a) isolated by ordinary methods. The binding capacity of anti–Lp(a) sorbent is 3 mg Lp(a) per 1 ml gel. Immunosorbent prepared in this study was reusable. It is suggested that anti–Lp(a) immunosorbent may be applied for clinical plasma adsorption therapy for the Lp(a)–apheresis procedure, especially for patients with high Lp(a) concentration in blood and with stenosis in coronary and cerebral arteries.
Artificial Connection Between Glucose Sensing and Insulin Delivery: Implications of Peritoneal Administration
Authors: Fischer Uwe , Freyse Ernst‐Joachim , Salzsieder Eckhard , Rebrin Kerstin
Published: July 2010

Abstract: The replacement of insulinogenic function in insulin‐dependent diabetes has to restore the feedback between intracorporal glucose and insulin. This has been accomplished by the following approaches: (a) the so‐called open‐loop insulin treatment by means of injections or pumps, employing laboratory or other extracorporal analytical devices and closing the feedback at large intervals only; (b) transplantation of insulin producing tissue and the bioartificial pancreas, employing the natural beta‐cell both for glucose sensing and insulin delivery; (c) implanted artificial drug delivery systems providing chemical feedback between intracorporal glucose and insulin release from a nonrefillable reservoir of limited capacity; (d) the intracorporal or paracorporal artificial beta‐cell comprising a glucose sensor (electrochemical or other type) that permanently delivers the signal to the computer‐controlled insulin pump. This artificial device works on the basis of an algorithm of glucose‐dependent insulin provision, compensating for the lack of other regulators, for the site of insulin administration, which is usually posthepatic, and for the kinetic properties of sensing system, e.g., a subcutaneous inserted amperometric electrode. Present experimental studies show that the pharma‐codynamics of peritoneally applied insulin may be implemented into a mathematical model of the overall glucose‐insulin system. They include absorption nearly as fast as after intravenous application, predominant portal inflow and approximately 30% hepatic removal. Feedback‐controlled peritoneal insulin administration by means of an artificial beta‐cell working on peripheral‐venous blood glucose monitoring results in normal gly‐cemic profiles under basal conditions and during oral glucose loads, if the pharmacodynamic properties of the peritoneal route are implemented into the insulin dosage algorithm.
Hematological Problems During the Use of Cardiac Assist Devices: Clinical Experiences in Japan
Authors: Tanaka Kuniyoshi , Sato Tomoaki , Kondo Chiaki , Yada Isao , Yuasa Hiroshi , Kusagawa Minoru , Nasu Michihiro , Okada Yukikatsu , Shornura Toyo
Published: July 2010

Abstract: Hematological changes occurring during use of left ventricular assist devices (LVADs) were evaluated in 3 patients suffering from postcardiotomy cardiogenic shock. LVAD treatment ranged from 6 to 9 days. During the procedure, no anticoagulants were used in the first two cases, while in the third case, a protease‐inhibiting agent, nafamostat mesilate (FUT‐175), was used. In the first two cases without any anticoagulants, fibrinopeptide A (FPA) and thrombin‐antithrombin III complex (TAT) increased markedly over the course of LVAD treatment, suggesting the excessive activation of the coagulatory system. The fibrinolytic system also became activated during LVAD treatment as was indicated by a marked increase in FDP‐D‐dimer and α2 plasmin inhibitor‐plasmin complex (PIC). Continual decreases observed in Factor XII and prekallikrein indicate that the coagulofibrinolytic activation occurring during LVAD treatment is presumably the result of contact activation of these factors due to interaction of blood with the internal surface of the LVAD. In the third case with FUT‐175, both coagulation and fibrinolysis were successfully maintained at minimum levels as was demonstrated by the extremely low levels of these molecular markers. There was also no significant consumption of any contact factors. FUT‐175 looks promising as an anticoagulant during the use of cardiac assist devices.
Noninvasive Control of Cardiac Output for Alternately Ejecting Dual‐Pusherplate Pumps
Authors: Snyder Alan J. , Rosenberg Gerson , Pierce William S.
Published: July 2010

Abstract: An artificial heart should be controlled in a non‐invasive fashion; the presence of the control system should pose no risk to the patient. Ideally, much of the control function would be attained passively, by designing the pumps and energy converter so that they naturally respond in an appropriate manner to changes in the circulation. We present methods of controlling both left‐right output balance and providing response to changing demands for blood flow for a class of total artificial hearts with implanted energy converters. Our balance control actively maintains left‐right balance, but does so in concert with the natural response of the pumps to changes in filling pressures. Cardiac output (CO) can be made to be sensitive to right atrial pressure, but peripheral resistance is our usual cue. Alternative means of determining the correct cardiac output are discussed.
Efficacy of Nafamostat Mesilate as a Regional Anticoagulant in Experimental Direct Hemoperfusion and in Plasma Exchange on Humans
Authors: Abe Hajime , Tani Tohru , Numa Kenji , Endo Yoshihiro , Yoshioka Toyokazu , Kodama Masashi
Published: July 2010

Abstract: As an anticoagulant, we compared Nafamostat mesilate (FUT) to heparin in experimental direct hemoperfusion (DHP) and studied the efficacy of FUT in clinical plasma exchange (PE). In in vitro study, FUT (5 μg/ ml) inhibited the activation of C4 more strongly than heparin (100 U/h), and larger dose of FUT (50 μg/ml) inhibited the activation of C3. Experimental DHP with FUT on jaundiced dogs was safely performed, but not with heparin. Clinical PE with FUT was safely performed and the hemostatic condition was not aggravated either during or after PE in patients with bleeding.
Long‐Term Cultures of Adult Mammalian Hepatocytes in Hollow Fibers as the Cellular Component of Extracorporeal (Hybrid) Liver Assist Devices
Authors: Jauregui Hugo O. , Muller Thomas E.
Published: July 2010

Abstract:A discussion of the treatment of liver insufficiency with extracorporeal (hybrid) liver assist devices (LADs) should address a definition of the types of liver failure susceptible to being treated by these devices as well as the modalities of in vivo and in vitro testing. Relevant to the first subject is the subject of pathogenesis of hepatic coma, which should be the target for the design of these LADs. Although this modality of therapy is new, it can be predicted that these devices will demand minimal safety conditions, i.e., the seeding with cells that are not tumorigenic or carrying viral particles. Among other topics to be considered in the development of LADs is the proper choice of hollow fiber to be used and the testing on proper animal models of hepatic failure. It is our philosophy that the long‐term culture of adult mammalian hepatocytes in hollow fibers is the basis for appropriate designs of this type of temporary liver support.
Detachable Shape‐Memory Sewing Ring for Heart Valves
Authors: Jansen Josef , Willeke Sebastian , Reul Helmul , RUM Günter
Published: July 2010

Abstract: The novel sewing ring concept consists of a detachable ring snap connection between valve housing or stent and suture cuff. The suture cuff itself is a memory metal ring of nickel‐titanium (NiTi) that is embedded within a textile fabric torus. After a special training program the ring can assume two geometric shapes when alternately cooled and heated. Due to this physical property, the sewing ring can be safely fixed within a groove of the housing or stent by changing between room and physiological temperature. This allows the surgeon first to implant the sewing ring followed by arbitrary positioning and final fixation of the valve by the shape‐memory effect. Additional advantages are an increased stiffening of the valve base for minimizing potential leaflet dysfunction, and reduced time and risk of implantation, particularly when a reoperation is necessary.
The Valvo‐Pump, An Axial Blood Pump Implanted at the Heart Valve Position: Concept and Initial Results
Authors: Yamazaki Kenichi , Okamoto Eiji , Yamamoto Katsuyuki , Mitamura Yoshinori , Tanaka Takashi , Yozu Ryohei
Published: July 2010

Abstract: The valvo‐pump, an axial nonpulsatile blood pump implanted at the heart valve position, has been developed. The valvo‐pump consists of an impeller and a motor, which are encased in a housing. An impeller with 5 vanes (22.0 mm in diameter) is used. The impeller is connected to a samarium‐cobalt‐rare earth magnet direct current (DC) brushless motor measuring 21.3 mm in diameter and 18.5 mm in length. Sealing is achieved by means of a ferrofluidic seal. A pump flow of 10.5 Limin was obtained at a pump differential pressure of 3.3 kPa (25 mm Hg), and a flow of 4.9 L/min was obtained at 7.0 kPa (53 mm Hg). Sealing was kept perfect against a pressure of 29.3 kPa (220 mm Hg) at 9,000 rpm.
Mechanical Circulatory Assist by a Roller Pump System Using Hydrophilic Heparinized Polymer Coated Tubing
Authors: Eguchi S. , Saito A. , Yamamoto K. , Moro H. , Ohzeki H. , Kawannmi O. , Futatni Y. , Noguchi N.
Published: July 2010

Abstract: We developed a circulatory assist system driven by a roller pump using hydrophilic heparinized polymer coated tubing. This system is easy to handle and does not require systemic heparinization. We applied it to 11 patients who failed to be weaned from cardiopulmonary bypass after open heart surgery. Left heart bypass was employed in 5 patients, right heart bypass in 1, combined left and right heart bypass in 2, and venoarterial bypass without oxygenation was done in 3 patients. The assisting flow rate ranged from 0.8 to 3.2 L/min, and the duration of the assist ranged from 5 h to 21 days. Six patients were weaned from this support, and 5 were discharged from the hospital. This system is beneficial for patients who failed to wean from cardiopulmonary bypass after cardiac surgery because of its simplicity and antithrombogenicity.
Improvement of the Hydrodynamic Response of a Ventricular Assist Device: A False Auricle Solution
Authors: Antoranz J. Carlos , Rubio Miguel A. , Duarte Juan , Fernandez‐Caleya Diego , Desco María M. , Cano María , García‐Barreno Pedro , Alvarez‐Valdivielso J. Miguel , del Cañizo Juan F.
Published: July 2010

Abstract: We propose a new design of the auricular cannula in ventricular assist devices (VADs), consisting of a collapsible large cannula with a capacity approximately equal to the ejection volume of the VAD. The device works as a false auricle and filters the negative pressure
Fibronectin Binding to Gelatin‐Impregnated Dacron (Gelseal) Prostheses
Authors: Carr H.M.H. , Vohra R. , Welch M. , Rooney O.B. , Sharma H. , Walker M.G.
Published: July 2010

Abstract: Endothelial cell adherence to uncoated gelatin‐impregnated Dacron (Gelseal) is poor but can be significantly improved by precoating with a suitable basement membrane such as fibronectin. To assess the suitability of fibronectin‐coated Gelseal for endothelial cell seeding, fibronectin binding to Gelseal and its dissociation kinetics were investigated. Fibronectin binding was quantified by radiolabeling human fibronectin with iodine 125, concentrations of 10, 25, 50, 150, and 250 γg/ml being used to coat Gelseal at 30, 60, and 90 min of incubation. The amount of fibronectin bound was directly proportional to the concentration used and increased with time of incubation (p < 0.05). However, the percentage attachment decreased with increasing concentration (p < 0.001). The number of molecules bound per centimeter squared of graft was calculated. In the first 30 min, 75% of bound fibronectin was lost after exposure to a flow rate of 200 ml/min in a pulsatile artificial circulation; thereafter, the fibronectin‐Gelseal bond was stable for up to 2 h.
Effects of Temperature on Phagocytosis of Human and Calf Polymorphonuclear Leukocytes
Authors: Utoh Junichi , Harasaki Hiroaki
Published: July 2010

Abstract: The in vitro effect of temperature on the phago‐cytic function of human and calf polymorphonuclear leukocytes (PMN) was studied. To observe the PMN phago‐cytic function (PPF) at various temperatures, PMN from healthy human and calf donors were incubated with serum‐opsonized fluorescent latex particles (diameter 1.66 γm) at 25, 37, 40, 42, 44, or 46°C for 1 h and then observed for their phagocytic activity by fluorescent microscopy. At 25, 40, and 42°C, human PPF was not significantly different from that at 37°C (87%, 89%, and 80% vs. 93%). At 44°C, PPF was noticeably depressed (19%, p < 0.05) when compared to that at 37°C. Next, to determine the critical temperature and duration of exposure that would irreversibly damage PPF, PMN were preincubated at 42, 44, or 46°C for 5–30 min before being subjected to a standard phagocytosis assay at 37°C. The human PPF was significantly depressed after 30 rnin at 44°C (33%, p < 0.05) or 10 min at 46°C (30%, p < 0.05). In conclusion, neither human nor calf PPF was significantly altered at and below 42°C. In contrast, the PPF was irreversibly and time‐dependently damaged when incubated at and above 44°C.
Small Soft Left Ventricular Assist Device Powered by Intraaortic Balloon Pump Console for Infants: A Less Expensive Option
Authors: Nojiri Chisato , Akutsu Tetsuzo , Koyanagi Hitoshi , Kolff Willem J.
Published: July 2010

Abstract: We have developed a pneumatically driven 20 cc soft ventricle for temporary right, left, or biventricular assist. The ventricle consists of a vacuum‐formed soft housing, diaphragm, tricuspid outflow valve, and biflap inflow valve. All components including inflow and outflow valves were made with Pellethane. The advantages of this blood pump are as follows: it eliminates use of the quick connect system and therefore is less thrombogenic; the biflap inflow valve provides low inflow resistance; the soft ventricle is easy to implant; the polyurethane valves eliminate blood damage and thromboembolism and are low in cost compared with mechanical valves; and the vacuum‐forming technique is reliable, fast, capable of mass production, and therefore inexpensive. We have already demonstrated in both in vitro and in vivo experiments that this ventricle has excellent hemodynamic performance with less blood damage and thrombogenesis. In this study, we evaluated the possible application of a well‐defined and widely distributed intraaortic balloon pump (IABP) console to the 20 cc left ventricular assist device (LVAD) driver. The pump was tested in 6 mongrel dogs (6 to 10 kg) using an IABP console. The pump was connected between the left atrium and the ascending aorta, placed paracorporeally on the chest wall, and driven at a synchronous or fixed rate mode without using vacuum. The 20 cc ventricle could maintain the same output as the conl. rol output of the natural heart at filling pressures of 5 to 10 mm Hg during the entire observation time of S h. Thus, this 20 cc soft ventricle has the potential to be widely used for the treatment of severe heart failure in infants because of its excellent hemodynamic performance, simplicity, and low cost.
Raising Plasma Phosphorus Levels by Phosphorus‐Enriched, Bicarbonate‐Containing Dialysate in Hemodialysis Patients
Authors: Yu A.W. , Soundararajan K. , Nawab Z. M. , Gandhi V.C. , Rahman M.A. , Popli S. , Ing T.S.
Published: July 2010

Abstract: In 6 hemodialysis patients, enriching the “base concentrate” of a bicarbonate‐containing dialysate‐gener‐ating system with phosphorus succeeded in raising plasma phosphorus levels.
Assessment of an Extracorporeal Liver Assist Device in Anhepatic Dogs
Authors: Kelly James H. , Koussayer Tarek , He Da‐er , Chong Maria G. , Shang Thomas A. , Whisennand Hartwell H. , Sussman Norman L.
Published: July 2010

Abstract: We have used an anhepatic dog model to demonstrate the efficacy of a bioartificial liver assist device. Six dogs underwent total hepatectomy. Three received only medical care (controls) while the remainder were connected to an extracorporeal liver assist device (ELAD). The control dogs failed to regain consciousness after anesthesia although all lived 4–5 h postoperativlely. Plasma ammonia concentration increased by an average of 2–50 μmol/L between the end of surgery and the demise of the animals. The treated dogs lived 3–12.5 h, and 2 of them required repeated doses of thiamylal sodium to maintain sedation. Plasma ammonia concentration was unchanged after connection to the ELAD except in the longest survivor, whose ammonia began to rise after 8 h on the ELAD. The short survival in the other 2 treated dogs was the result of uncontrolled intraabdominal bleeding. This device is capable of replacing the metabolic function of the liver, and might provide hepatic support in patients awaiting transplantation or in fulrninant hepatic failure.
In vitro Study of Multicellular Hepatocyte Spheroids Formed in Microcapsules
Authors: Ito Y. , Chang T.M.S.
Published: July 2010

Abstract: To make highly differentiated encapsulated he‐patocytes, we formed hepatocyte spheroids in microcapsules in cultures. Hepatocytes isolated from rats were encapsulated in alginate‐poly‐L‐lysine artificial cells and cultured under different medium conditions. When high molecular weight poly‐L‐lysine was used to make the capsule membrane, the hepatocytes aggregated and formed spheroids inside microcapsules within 48 hs. We studied the viability and function of encapsulated hepatocyte spheroids; free hepatocyte spheroids; nonaggregated encapsulated hepatocytes; and free hepatocyte monolayers. Cell viability and protein‐producing ability were monitored for up to 30 days. Hepatocyte spheroids in the encapsulated or free form remained viable and continued to secrete proteins throughout the 30 days of observation. The viability and function of nonaggregated hepatocytes in the encapsulated or free form declined rapidly. These results suggest that the tridimensional structure of the spheroids may be important in maintaining the viability and function of encapsulated hepatocytes.
Systemic Levels of Tumor Necrosis Factor Alpha During Hemodialysis with Cellulosic Membranes: No Effect of the Sterilization Procedure
Authors: Jörres Achim , Safak Hülya , Froese Peter , Fischer Christoph , Müller Christian , Gahl Gerhard M. , Vienken Jörg
Published: July 2010

Abstract: Extractable constituents of dialyzer membranes (e.g., monomers and †‐glucans) may induce the production of cytokines in vitro. We therefore studied circulating tumor necrosis factor alpha (TNFα) levels in 23 stable hemodialysis patients during treatment with dry Cuprophan membranes (ETO‐sterilized n = 10, steam‐sterilized n = 13) longitudinally over a period of 4 weeks. After 4 weeks, those 5 patients of each group showing the highest TNFα levels were switched to steam‐sterilized, wet Cuprophan membranes. No significant increase in plasma TNFα was observed during hemodialysis with either ETO‐ or steam‐sterilized dry Cuprophan membranes. A substantial TNFα increase (≥ 100% compared to pre‐HD values), however, was observed during 14 of 84 treatment sessions. In 5 selected patients with ETO‐sterilized, dry Cuprophan dialyzers, TNFα rose from (mean ± SEM) 17.2 ± 3.0 (pre‐HD) to 20.9 ± 6.2 (120 min) and 21.9 ± 4.5 pg/ml (240 min). Corresponding levels in patients with steam‐sterilized, dry Cuprophan were 16.2 ± 5.4 (pre‐HD), 21.9 ± 6.8 (120 min), and 16.0 ± 3.7 pg/ml (240 min), respectively. There was no difference between ETO‐ and steam‐sterilized dialyzers. No significant reduction in mean TNFα plasma levels or in frequency of elevated peak levels was achieved when these patients were switched to wet Cuprophan dialyzers for another 4 weeks. It is suggested that an induction of elevated TNFα levels during hemodialysis is possible but is not observed regularly during treatment with Cuprophan membranes. Moreover, wet storage of dialyzers (allowing for better extraction of cytokine‐inducing material) did not prove to be superior to conventional dry storage in terms of cytokine generation.
Polylysine‐Immobilized Chitosan Beads as Adsorbents for Bilirubin
Authors: Chandy Thomas , Sharma Chandra P.
Published: July 2010

Abstract: Hyperbilirubinemia generally relates to an elevated bilirubin level in the blood and is usually an indication of a disease of the blood, liver, or biliary tract. Hemo‐perfusion using synthetic resins as sorbents has been one of the ways to reduce bilirubin. In this study, chitosan, a natural polysaccharide having structural characteristics similar to glycosaminoglycans and which is nontoxic and biocompatible, has been used for bilirubin binding. Several layers of poly‐l‐lysine have been coated covalently onto chitosan beads, using N2 plasma and carbodiimide treatments. Such surface‐modified chitosan beads exhibited high binding affinities for bilirubin (1.13 ± 0.18 mg/g beads) in aqueous phosphate buffer solutions at 4°C in relation to activated charcoal (0.74 ± 0.2 mg/g). The poly‐lysine‐coated resins have been reported to have an improved binding affinity for bilirubin over cholestyramine. It seems that the surface‐immobilized polylysine has an increased bilirubin binding affinity and is highly stable. The binding capacity is proportional to the amount of polylysine bonded to the chitosan beads. The hemolytic potential of all modified beads is compatible with polystyrene control tubes. Studies were also performed against albumin as proof of specificity toward bilirubin binding. The albumin‐coated beads have shown the highest blood compatibility and selectivity over the other modified beads. However, it appears that polylysine‐modified chitosan may be an excellent sorbent system for hemoperfusion due to its high binding affinity, capacity, and blood compatibility. Further studies are needed to determine its behavior under clinical conditions.
A Compact Centrifugal Pump for Cardiopulmonary Bypass
Authors: Sasaki Tatsuya , Jikuya Tomoaki , Aizawa Takeshi , Shiono Motomi , Sakuma Ichiro , Takatani Setsuo , Glueck Julia , Noon George P. , Nosé Yukihiko , DeBakey Michael E.
Published: July 2010

Abstract: A majority of the cardiopulmonary bypass (CPB) systems still utilize bulky roller pumps. A direct‐drive small centrifugal pump intended for second‐generation CPB pump has been developed. The pump has a 50 mm diameter impeller and provides a 6 L/min flow at 3,000 rpm against 300 mm Hg. A flexible drive shaft allows us to separate the pump head from the console resulting in easier manipulation. An in vitro study showed that the pump generated less hemolysis (index of hemolysis = 0.0011, comparable to the value for Bio‐medicus BP‐80).

To improve blood flow around the shaft‐seal region and to reduce thrombus formation around the shaft, six holes were drilled through the impeller. In biventricular bypass experiments using calves, our pump demonstrated excellent antithrombogenicity and durability for 48 h. And the compact and atraumatic centrifugal pump system showed excellent performance and easy manipulation under acfual CPB conditions in animal.
Evaluation of Two Epoxy Ether Compounds for Biocompatible Potential
Authors: Lohrr Jeffrey M. , Budig Lita , Sagartz John , Girida Sarah , Thyagarajan Kalathi , Tu Roger
Published: July 2010

Abstract: Bovine arterial tissue exposed to two epoxy ether compounds (Denacol EX‐313 and Denacol EX‐810) was evaluated for its biocompatible potential by in vitro and in vivo test procedures. The battery of test procedures included percent Inhibition of Cell Growth, Medium Eluate Method (MEM), Agar Overlay (AO), Blood Compatibility, Acute Mouse Systemic Injection, Rabbit lntracutaneous Irritation, Rabbit Subcutaneous Implantation, Guinea Pig Maximization, and Ames Tests. The epoxy exposed tissue was found to be noncytotoxic, non‐mutagenic, and biocompatible by the test methods employed. In addition, the maximum concentrations of the unreacted Denacol EX‐313 and EX‐810 solutions found to demonstrate noncytotoxic reactions by the MEM and AO procedures were identified as 55 and 60 ppm for the MEM and 150 and 200 ppm for the AO procedure, respectively. These studies suggest that Denacol EX‐313 and EX‐810 are acceptable solutions for the processing of implantable tissue provided the epoxy residuals remain below those levels found to be cytotoxic.
Alternative Descriptions of Combined Diffusive and Convective Mass Transport in Hemodialyzer
Authors: Waniewski Jacek , Lucjanek Piotr , Werynski Andrzej
Published: July 2010

Abstract: Two alternative versions of the mathematical description of the combined diffusive and convective membrane transport in hemodialyzers were compared using the one‐dimensional theory of hemodialyzers. The first version is based on the assumption of homogeneity of the membrane. The second version is a widely used “ad hoc” formulation, which can be interpreted as a description of the membrane as tighter at the dialysate side than at the blood side. Theoretical predictions of the increase of dialyzer clearance caused by ultrafiltration, as assessed by transmittance coefficient, were compared to experimental data about transport of small solutes (urea, creatinine, and sodium) as well as middle molecules (vitamin B12) in three types of hollow‐fiber hemodialyzer. For one type of dialyzer, the theory assuming the homogeneous membrane yielded the correct predictions for the small solutes. For two other types of dialyzer, the alternative version of the theory was adequate. For vitamin B12, the experimental values of transmittance coefficient were between the values predicted by the two versions of the theory for all three types of hemodialyzer. Thus, the two versions should be considered as a possible adequate description of solute transport in hemodialyzers.
A Seal‐less Centrifugal Pump (Baylor Gyro Pump) for Application to Long‐Term Circulatory Support
Authors: Minato Naoki , Sakuma Ichiro , Sasaki Tatsuya , Shiono Motomi , Ohara Yasuhisa , Takatani Setsuo , Noon George P. , Nose Yukihiko
Published: July 2010

Abstract: We are developing a new centrifugal pump, the Baylor Gyro Centrifugal Pump (Gyro Pump), which can function for more than 2 weeks. The concept of the Gyro Pump is that a one‐piece rotor‐impeller with embedded permanent magnets, driven directly by a brushless direct current motor stator placed outside, rotates like a “gyro‐scope,” and the rotor‐impeller is supported by one pivot bearing at the bottom in accordance with the gyroscopic principle. This concept enables us to eliminate a driving shaft and a seal between the driving shaft and the blood chamber, which results in extending the life of the centrifugal pump. The blood passes through the space between the motor stator and the rotor to the impeller portion. In this preliminary phase, two pivot bearings were applied to support the rotor‐impeller at the top and the bottom inside the blood chamber. Both pivot bearings showed less blood trauma and less thrombogenicity in in vitro and in vivo studies. The Gyro Pump is a promising second‐generation centrifugal pump for long‐term circulatory support in the near future.
Assisted Circulation Using Cardiomyoplasty Together with Aortomyoplasty
Authors: Takahashi Ryuichi , Yozu Ryohei , Kurosaka Yu , Kawada Shiaki
Published: July 2010

Abstract: Both dynamic cardiomyoplasty and counterpulsation by the synchronous paced contraction of skeletal muscles in aortomyoplasty can improve ventricular function. The goal of this study was to clarify the effect of cardiomyoplasty combined with aortomyoplasty on cardiac dysfunction in dogs. The percentage of increase in various hemodynamic parameters was calculated during assisted and unassisted cardiac cycles and was compared for three groups: cardiomyoplasty only (Group A), aortomyoplasty only (Group B), and both methods combined (Group C). In Group A, the left ventricular pressure (LVP), systolic aortic pressure (systolic AoP), and dp/dt of LVP (LVdp/dt) increased significantly; the diastolic aortic pressure (diastolic AoP) did not change; and the endocardial viability ration (EVR) decreased during assisted cardiac cycles. In Group B, the diastolic AoP and EVR were improved significantly, but the LVP, LVdp/dt, and systolic AoP were unchanged during assisted cardiac cycles. In contrast to Groups A and B, all parameters were improved in Group C during assisted cardiac cycles. Cardiac assistance using cardiomyoplasty together with aortomyoplasty was more effective than either procedure used alone.
Bulk Mass Transport Limitations during High‐Flux Hemodialysis
Authors: Zydney Andrew L.
Published: July 2010

Abstract: Solute clearance during high‐flux hemodialysis is determined by the combined effects of solute convection and diffusion in the membrane, blood, and dialysate. Previous studies have focused almost entirely on the membrane transport phenomena, largely ignoring the potential contribution from bulk mass transport across the fluid boundary layers in the blood and dialysate. This study presents a theoretical analysis of the coupled transport equations in the membrane, blood, and dialysate including the contributions from both convective and diffusive transport in each of these regions. The resulting theoretical expression for the solute flux demonstrates that bulk mass transfer limitations can have an important effect on solute transport and, in turn, solute clearance during high‐flux hemodialysis.
Alprostadil: An Effective Antiplatelet Agent for Calves
Authors: Jaarsma Ruurd L. , Mohammad S. Fazal , Burns Gregory L. , Olsen Don B.
Published: July 2010

Abstract:Aspirin and other nonsteroidal, antiinflammatory drugs inhibit human platelets, but their effect as an antiplatelet agent on bovine platelets is not certain. Since calves are used for cardiovascular implant research, need exists for an effective antiplatelet agent for this animal model. After screening a number of potential antiplatelet drugs for calves, Alprostadil (prostaglandin E1) appeared to be the most promising. Alprostadil was administered (intravenous continuous drip) to 8 calves. The concentration of the drug administered was gradually increased until 50% inhibition of platelet aggregation was obtained. Platelet function, blood pressure, body temperature, and hematologic parameters were closely monitored. For in vitro evaluation, Alprostadil was added to human or bovine blood, and the platelet aggregation and cyclic adenosine monophosphate levels were measured. Alprostadil inhibited both bovine and human platelets, although bovine platelets were relatively more responsive to this drug. At an infusion rate of approximately 0.20 pg/kg/min in vivo, Alprostadil showed 50% inhibition of platelet aggregation with slightly decreased blood pressure (7 ± 6 mm Hg) but no adverse effects. Complete reversal of in vivo platelet inhibition was noted within 24 h after cessation of drug administration. This short half‐life and the lack of significant adverse effects make Alprostadil an attractive antiplatelet agent for calves with cardiovascular implants.
21ST ANNUAL MEETING ON ARTIFICIAL HEARTS AND ASSISTED CIRCULATION
Authors: Mitamura Yoshinori
Published: July 2010

The primary concern of the meeting was free discussion. A part of the discussion is summarized below.
Nonpulsatile Mode of Blood Flow Required for Cardiopulmonary Bypass and Total Body Perfusion
Authors: Nosé Yukihiko
Published: July 2010

Abstract: Higher morbidity and mortality rates are seen after the use of cardiopulmonary bypass in infants and elderly patients. Clinical procedures acceptable for adult patients may not be acceptable for them. Infants require more effective tissue gas exchange or tissue perfusion because of their active metabolic status. On the other hand, vascular systems of elderly patients are more rigid and do not have enough reserve capacity for nonpulsatile perfusion compared to young adults. More effective tissue perfusion is needed for them during cardiopulmonary bypass. Traditionally, we utilize a nonphysiological, non‐pulsatile pump and perfuse the patients with bypass flows below their resting cardiac outputs (70–80%). In our experience, in general, it is necessary to have approximately 20% higher cardiac output in cases where we use a nonpulsatile mode of total body perfusion compared with a pulsatile mode of perfusion. In addition, higher bypass flow is expected to be required for infants because of their higher metabolic rate and for elderly patients because of their more rigid vascular structure.
Renal Effects of Multiple Infusion of Pyridoxalated‐Hemoglobin‐Polyoxyethylene Conjugate (PHP) Solution in Dogs
Authors: Takahashi Tsuyoshi , Iwasaki Keiji , Malchesky Paul S. , Harasaki Hiroaki , Matsushita Michiaki , Nosé Yukihiko , III Henry Rolin , Hall Phillip M.
Published: July 2010

Abstract: Pyridoxalated‐hemoglobin‐polyoxyethylene conjugate (PHP), which is made from out‐dated human red blood cells by two major chemical modifications, namely pyridoxalation and conjugation with polyoxyethylene (POE), is currently under development as a physiological oxygen carrier. This study assessed the effects of PHP‐88 solution, which contains 8% (wt/vol) each of hemoglobin (Hb) and maltose, on renal function when it was infused 3 times every other day into the intact circulation of 8 dogs (5 dogs for the PHP group and 3 for the control group; 20 ml/kg for the first infusion, and 10 ml/kg each for the second and third infusions, at the rate of 2.5 ml/h/kg). Serial determinations of glomerular filtration rate (GFR) and renal plasma flow (RPF) were carried out pre‐ and postinfusion for up to 3 months along with measurements of blood and urine analyses, urine output rate, fractional excretion of sodium (FES), and free water clearance (CH2O). The results showed that plasma colloid osmotic pressure (COP) elevated an average of 3.3 mm Hg (p = 0.0085), and GFR and RPF tended to increase by 13% (NS) and 38% (NS), respectively, immediately after the third infusion with PHP solution. Urine output rate increased during and after the infusion, and FES and CH2O also increased for 24 h after the infusion in both groups. Blood urea nitrogen, serum creatinine, and serum Na+ concentrations were not affected greatly by the infusions, but hematocrit was decreased by 8% in the PHP group, indicating approximately a 42% expansion of plasma volume. These changes were observed to return to their preinfusion levels by 1 week postinfusion. Renal histology of the PHP group obtained at 2 weeks postinfusion revealed vacuole formation in the proximal tubules which was not associated with any pathologic changes indicative of cell death or regeneration. In 4 out of 5 dogs at 3 months postinfusion (necropsy), the vacuoles were not present. Though urinary N‐acetyl β‐glucosaminidase (NAG) activity had significantly increased after infusion, it returned to the preinfusion level by 1 month postinfusion. No detrimental effect of vacuoles on the assessed renal tubular functions was confirmed in the present study. The result demonstrated that multiple infusions of PHP solutions were well tolerated in normal dogs, and the observed effects were conceived predominantly attributable to the physiological response of the kidneys to an oncotic load into the circulation, which produced plasma volume expansion.
A Novel Electromechanical Drive for a Tether‐Free Implantable Ventricular Assist Device
Authors: Feldman Louis W. , Harris Russell L. , Noon George P.
Published: July 2010

Abstract: A tether‐free ventricular assist device (VAD) based on a novel electromechanical drive was prototyped and evaluated. The unit can be adapted for implantation. The device utilizes a bladder‐type ventricle taken from a pneumatically driven VAD. In mock loop testing, the unit has met the design capacity of 6 L/min against a pressure head of 150 mm Hg. The efficiency of the device allows it to operate at design flow and pressure for periods of up to 8 h when powered by a single rechargeable battery pack weighing less than 5 kg. The mechanism consists of a seamless sac‐type bladder situated between hinged plates actuated by a motor‐driven bell‐and‐crank linkage. Cycle parameters are controlled by a microprocessor‐based servomotor drive.
Adverse Events of Subcutaneous Recombinant Human Erythropoietin Therapy: Results of a Controlled Multicenter European Study
Authors: Klinkmann Horst , Wieczorek Lothar , Scigalla Paul
Published: July 2010

Abstract: In a controlled European multicenter study, clinical tolerance of subcutaneously administered recombinant human erythropoietin (rh‐EPO) therapy and its influence on the course of illness in 362 hemodialyzed patients (162 males, 200 females) from 16 European dialysis centers was studied. Of these, 181 patients served as a control group in the first year and received rh‐EPO therapy in the second year. Of the 837 adverse events that occurred, 277 were classified as serious and 560 as nonserious. Thirty‐two deaths have been reported for the study population: 18 in the control group and 14 in the therapy group. The individual analysis of the serious adverse events including death demonstrates a protective effect of rh‐EPO on the high‐risk cardiovascular situation of dialysis patients. Hypertension was no problem, and under rh‐EPO therapy an increase in resistance to infection was observed. Subcutaneous rh‐EPO treatment might have an even better safety profile than intravenous application.
Some Topics in Bio‐Fluid Mechanics
Authors: Tanida Yoshimichi
Published: July 2010

Abstract: Recently, several biomedical phenomena have been studied from the internal fluid‐dynamic point of view because their causes are attributed mostly to flow phenomena. The present paper reviews some current topics related to the unsteady flows, first in the large blood vessels and then in the lung, and shows how they are studied from the engineering point of view.
Beneficial Circulatory Support by Left Heart Bypass with a Centrifugal (BioMedicus) Pump for Aneurysms of the Descending Thoracic Aorta
Authors: Ataka Keiji , Okada Masayoshi , Yamashita Chojiro , Kujime Keiichiro , Kihana Eiichi , Yoshimura Naoki , Azami Takashi
Published: July 2010

Abstract: A comparative study between left heart bypass with a centrifugal (BioMedicus) pump and with a temporary external shunt was performed to assess the efficacy of distal organ perfusion in the surgical treatment of 31 patients with aneurysm of the descending thoracic aorta. Eighteen patients were supported with a centrifugal pump, and the remaining 13 were supported by temporary shunt with either a Gott shunt or a Dacron graft. Heparinless bypass with a centrifugal pump provided a significant decrease of intraoperative blood loss and blood transfusion by the combined application of Cell‐Saver. The pressure difference between upper and lower extremities decreased (p < 0.05) in the centrifugal pump group even with aortic cross‐clamping, and the urine output increased during operation. Among 13 patients supported with the temporary shunt, 3 had postoperative renal failure, and 2 died of it. All patients with a centrifugal pump survived without any complications. It could be concluded that the left heart bypass with a centrifugal (BioMedicus) pump was safe and was favorable for support of the distal circulation during aortic cross‐clamping and to prevent ischemic complications such as renal failure and spinal cord injury.
Development of the Terumo Capiox Centrifugal Pump and Its Clinical Application to Open Heart Surgery: A Comparative Study with the Roller Pump
Authors: Nishida Hiroshi , Yamaki Fumitaka , Nakatani Hayao , Endo Masahiro , Koyanagi Hitoshi , Oshiyama Hiroaki , Horiuchi Kunio , Kijima Toshihiko , Nojiri Chisato , Fukasawa Hiromichi , Akutsu Tetsuzo
Published: July 2010

Abstract: We have developed the Terumo Capiox centrifugal pump (CXP), which consists of a rotor having a unique straight‐path design to reduce pump rotational speed without decreasing hydraulic efficiency. The CXP was tested in vitro for blood trauma with a specially designed test circuit using fresh bovine blood. The Biopump (BP) (Medtronic, Minneapolis, MN, U.S.A.) and the roller pump (RP) were used as controls. The CXP demonstrated the smallest elevation of free plasma hemoglobin compared with the BP and the RP. The CXP was then applied to cardiopulmonary bypass (CPB) in 10 patients (CXP group) who underwent elective coronary artery by‐pass grafting (CABG), and the results were compared with those for a comparable roller pump group (RP group). Free plasma hemoglobin level, platelet count, and serum β‐thromboglobulin (β‐TG) level were measured during CPB. There were no CXP‐related complications nor hemodynamic abnormalities during CPB. The CXP group demonstrated less hemolysis and less platelet depletion than the RP group. Furthermore, the serum β‐TG level was significantly lower in the CXP group than in the RP group. The CXP showed excellent hemodynamic performance with less blood trauma both in vitro and in clinical application to open heart surgery. Thus, the CXP has significant potential to be safely applied to CPB for open heart surgery and circulatory support.
Clinical Evaluation of a New Dialyzer, FLX‐12 GW, with a Polyester‐Polymer Alloy Membrane
Authors: Stein G. , Günther K. , Sperschneider H. , Carlsohn H. , Huller M. , Schubert K. , Schaller R.
Published: July 2010

Abstract: The performance of a membrane in renal failure therapy is determined by its structure, its overall mass transfer properties, and its blood compatibility. In this regard. removal of β2‐microglobulin (β2M) has become a major objective of dialysis therapy. In the present study, a newly developed high‐flux membrane composed of a polyester‐polymer alloy (PEPA) with the components of polyarylate and polyethersulfone (dialyzer FLX‐12 GW; Nikkiso Co., Japan) has been evaluated with regard to both hiocompatibility and elimination capacity for β2M during hemodialysis of 8 stable chronic uremic patients. The clearance values of low molecular weight solutes were in the same range as those reported for high‐flux dialyzers of comparable surface area. There was no drop in leukocyte counts and only a minimal fall in platelet counts nearly in the same range as has been observed by other investigators using polyamide membrane. C3a Des Arg generation was low, and C5a Des Arg formation was not significantly influenced. There was a sharp drop in the serum β2M level (‐35%) during dialysis with a clearance between 59.7 ± 5.6 ml/min (QB 200 ml/min) and 70.1 ± 9.7 ml/min (QB 300 ml/min), respectively. Accordingly, the sieving coefficient was calculated to be 0.2 at 30 min after start of dialysis and 0.6 1 h later. The membrane was able to remove 184.0 ± 22.3 mg/4 h due to an apparent rate of adsorption during the first hour of treatment in combination with high transmembrane transfer in the following time.
Early Experimental Studies on Hemoperfusion as a Treatment Modality for Acute Radiation Disease
Authors: Nikolaev V.G. , Pinchuk L.B. , Umansky M.A. , Pinchuk V.G. , Burushkina T.N. , Petrenko S.V. , Rodionova N.K. , Snezhkoua E.A. , Bichkoua N.P.
Published: July 2010

Abstract: First results of the studies on hemoperfusion therapy of acute radiation disease that were conducted in Kiev in 1976 are presented. In these studies, 69 mongrel dogs were exposed to irradiation at a dose of 525 rad (5.25 Gy). It was proved that hemoperfusion through uncoated synthetic activated carbons led to a noticeable increase in their survival rate, from 3.2% in the control group (n = 31) to 68.4% and 62.4% for the dogs that received extracorporeal treatment at 2 h (n = 19) and 24 h (n =‐19) after irradiation, respectively.