bluuebunny/crossref_metadata_2025 huggingface dataset:
Biocompatibility: Bioengineering Aspects
Authors: Murabayashi Shun , Nosé Yukihiko
Published: November 2008

Abstract: Bioengineers have contributed to biocompatibility research. Many materials have been designed, synthesized, and characterized by use of various analytical instruments. The blood compatibility of materials has been studied by focusing on the blood‐material interfacial reactions. Although much information has been accumulated regarding such local reactions, understanding of biocompatibility is still limited. A more global approach to study is needed. A new approach to understanding biocompatibility is proposed and discussed. Three points are stressed: interaction within body's defense system and its effect on blood‐material reactions; induction of a systemic reaction by a local reaction, which then affects the blood‐material interaction; the time sequence of such interactions between local and systemic reactions. To establish a logical approach to study biocompatibility is most important at this moment for the future progress in biocompatibility research.
Control and Driving of Pneumatic Total Artificial Hearts TNS‐BRNO‐II and‐III in Long‐Term Experiments
Authors: Vasku Jan , Urbánek Petr , Vašků Jaromir , Černý Jan , Smutný Miloš , Urbánek Erich , Suchánek Josef , Gregor Zdeněk , Dostál Miloslav , Guba Peter , Sládek Tomáš , Wendsche Peter , PavlíČek Viktor , Trbušek Vojtěch , Šotolová Olga , Úlehla Tomás , Fiala Vlastimil
Published: November 2008

Abstract: Hemodynamic analysis was carried out during long‐term experiments with the pneumatic total artificial hearts TNS‐BRNO‐II and TNS‐BRNO‐III to determine standard methods of starting artificial hearts and criteria for their long‐term operation in vivo. In long‐term experiments, regulatory mechanisms automatically regulating the systole length and diastolic aspiration pressure have also been verified. Comparison of hemodynamic variables obtained from invasive measurements with pneumatic pressure curves permitted the control and monitoring of the experiment in its entirety by noninvasive methods only. The control of the artificial heart using the Chirasist TN 3 and Chirasist TN 4 was adapted to specific properties of the pumps, above all to the functions of the atypical inlet valves. The terminal stages of the experiments have shown that a 100‐ml pump can ensure survival of experimental calves up to 210 kg body weight.
Rapid High‐Efficiency Hemodialysis
Authors: Collins Allan , Ilstrup Karen , Hanson Ginger , Berkseth Robert , Keshaviah Prakash
Published: November 2008

Abstract: Reductions in treatment time are attractive for patients and dialysis centers. However, there are concerns related to treatment adequacy and increased intradialytic symptoms. Treatment times were progressively reduced in 12 stable patients on standard 4‐h acetate hemodialysis, solute clearances being increased proportionately, until the tolerance limit manifested by increased complications or 2.5 h of treatment was reached. Once shortened schedules (mean reduction ˜31%) were achieved, a 2‐month surveillance period was initiated, followed by 2 additional months of bicarbonate therapy, treatment time being unchanged. Rapid bicarbonate hemodialysis was associated with a significantly lower incidence of hypotension, nausea, and vomiting than rapid acetate or standard acetate therapies. Fluid removal was comparable with that of standard treatment, and serum chemistry levels remained stable. Based on the success of these studies treatment times have been reduced in > 200 patients with high‐efficiency bicarbonate therapy for long‐term evaluations.
Hepatic Assist: Present and Future
Authors: Mito Michio
Published: November 2008

Abstract: Fulminant hepatic failure due to acute massive liver cell necrosis is a complex pathophysiological entity, and treatment is still unsatisfactory. Artificial liver supports such as hemodialysis, hemoperfusion, and plasmapheresis have recently been used clinically to treat fulminant hepatic failure. However, survival rate has not improved as expected, although the consciousness of the patient has improved frequently. In this article the present status of clinical artificial liver support and basic research of hybrid artificial liver will be discussed. Moreover, the future aspects of total artificial liver support and hepatocyte transplantation for chronic liver failure will be introduced.
Particle Spallation Induced by Blood Pumps in Hemodialysis Tubing Sets
Authors: Barron David , Harbottle Sarah , Hoenich Nicholas A. , Morley Adrian R. , Appleton David , McCabe John F.
Published: November 2008

Abstract: The repeated flexion and compression of pump segments by the rollers of peristaltic pumps results in cracking and abrasion of the inner surfaces of the pump segment, leading to shedding of particles into the extra‐corporeal circuit. A series of studies to assess the rate of particle release from silicone rubber, polyvinyl chloride (PVC), and Pivipol, a coextruded polyurethane‐coated PVC tubing, when these materials were used with blood pumps of the type found in hemodialysis units, was un dertaken. The studies show that with all tubing/pump combinations there is an overall increase in the total number of particles released, but an analysis of the par tide size distribution indicates that the majority of the particles are < 16 μm in diameter. The rate of increase may be reduced, however, by decreasing the occlusion pressure.
Thromboembolic Complications of the Jarvik‐7 Total Artificial Heart: Case Report
Authors: Levinson Mark M. , Smith Richard G. , Cork Randall C. , Gallo Joseph , Emery Robert W. , Icenogle Timothy B. , Ott Richard A. , Burns Gregory L. , Copeland Jack G.
Published: November 2008

Abstract: The Jarvik‐7 total artificial heart (TAH) has now been implanted in seven patients, with four (57%) suffering cerebral embolic events. Functional recovery in two patients was impaired by subsequent intracranial hemorrhage from anticoagulant therapy. The findings of a Jarvik‐7 TAH explanted following a cerebral embolus are reported here. Thrombotic deposition was seen in the inner crevice formed between the two components of the aortic quick connector. In addition, deposition was seen around all four valves in the crevice formed between the valve ring and the plastic valve housing. On the atrioventricular valves, the deposition in this crevice was most severe on the outflow surface adjacent to the minor flow orifice. On the pulmonic valve, deposition was seen around the entire circumference of both the inflow and the outflow crevices. No thrombi were seen on the diaphragm, the diaphragm‐housing junction, or the housing of the left ventricle. Hypercoagulability of the patient's blood gradually developed during implant, reaching a maximum on the evening before the clinical embolus. Increasing resistance to heparin was also demonstrated by in vitro testing.
Preparation and Evaluation of Hemoglobin‐Polyethylene Glycol Conjugate (Pyridoxalated Polyethylene Glycol Hemoglobin) as an Oxygen‐Carrying Resuscitation Fluid
Authors: Iwasaki Keiji , Iwashita Yuji
Published: November 2008

Abstract: Human hemoglobin was pyridoxalated and subsequently coupled with the activated ester of polyethylene glycol (PEG) to provide an oxygen‐carrying resuscitation fluid. The PEG conjugate of pyridoxalated hemoglobin (pyridoxalated PEG hemoglobin) has a longer half‐life in the circulation (12.8 h) than does hemoglobin (2.2 h) when the solutions are exchange‐transfused by ˜60%. The P50 of pyridoxalated PEG hemoglobin, which is the partial pressure of oxygen at which one‐half of the absorbed oxygen is released, was 21.3 ± 1.4 mm Hg (mean ± SD, n = 5) (37°C, pH = 7.4), which is close to that of human whole blood (25.9 ± 0.6 mm Hg). The colloidal osmotic pressure and the viscosity were 36.5 ± 2.4 mm Hg (n = 5) and 2.6 ± 0.4 cp (n = 5), respectively. The results indicate that the pyridoxalated PEG hemoglobin solution has favorable properties for use as an oxygencarrying resuscitation fluid.
Precongress Symposium: Vascular Prostheses
Authors: Wesolow A. , Kambic H.
Published: November 2008

Abstract: The U.S. Food and Drug Administration (FDA) believes that a performance standard for vascular graft prostheses ≥6 mm in diameter is necessary to control the risks associated with such devices. These include infection, occlusion, noncompliance, porosity issues, structural integrity, and nonbiocompatibility. In 1979 the FDA published its proposed rule to classify these grafts into Class II devices. The data supporting the need for a performance standard have come from FDA Advisory Committee Proceedings, contract safety and performance studies (1979), and the recent Vascular Graft Safety and Update Symposium (1984). Voluntary standards have been submitted by the AAMI (Association for the Advancement of Medical Instrumentation) VP‐D/84 and the ISO/DP 7198. The amendment to the Federal Food, Drug, and Cosmetic Act, known as the Medical Device Amendment of 1976, under Section 514 presents the procedure for the development of performance standards. This article describes the participation by those regulatory, manufacturing, tester, and user groups most affected by the standards and most directly involved in standards development procedures.
Materials and Their Specifications for Vascular Prostheses. Specifications and Performance Standards
Authors: Lontz John F.
Published: November 2008

Abstract: Specification and performance standards represent distinctly different criteria for safe and effective cardiovascular materials and devices, in distinct areas of materials and device conversions, with consideration of implant as well as physiological assault. Cardiovascular device failures need more definitive, realistic, and creative approaches to devising standards of performance with relevance to the physiological environment.
Synthesis and Secretion of Protein by Hepatocytes Entrapped within Calcium Alginate
Authors: Miura Yoshiharu , Akimoto Toshihoko , Kanazawa Hiroko , Yagi Kiyohito
Published: November 2008

Abstract: The ability of entrapped hepatocytes to secrete plasma proteins was examined for the purpose of developing a biological artificial liver. Hepatocytes were isolated from adult rat liver by perfusion with collagenase. Isolated hepatocytes were entrapped within calcium alginate. The entrapped cells induced tyrosine aminotransferase (TAT) in the presence of dexamethasone and dibutyryl‐cyclic AMP and retained the ability to induce TAT for 7 days. Moreover, entrapped cells could synthesize and secrete a biologically active form of coagulation Factor II, prothrombin. Two plasma proteins, lecithin: cholesterol acyltransferase and cholinesterase, were also secreted into the medium. Thus, hepatocytes within calcium alginate showed liver‐specific characteristics, and these activities were almost comparable with those of monolayer‐cultured cells.
The Artificial Heart: Pursuit of a Noninvasive Method for Determining Atrial Pressures
Authors: Blaylock Robert C. , Nielsen Steven D. , Morgan David L. , Lioi Anthony P. , Morgan James M. , Olsen Don B.
Published: November 2008

Abstract: The use of conventional open‐port catheters in total artificial heart (TAH) research shortens the survival time of recipients owing to sepsis and embolism caused from the catheters. Valuable data are lost when an open‐port catheter clots off, and transducer position must be keyed to the level of the atria for accuracy. The need for an accurate, easily obtainable, noninvasive method for measuring atrial pressure is of obvious value. Such a method has been developed in vitro using a device that measures the stroke volume of a pneumatic ventricle. The stroke volume is obtained by quantifying the amount of air exiting a pneumatic TAH in diastole. Using this information ventricular filling rates can be calculated by the stroke volume measurement device, and these rates are correlated to measured atrial pressures. There is no need to continually adjust transducer levels in relation to the atria with this system. The data show an average percentage error of 2.4 of full scale (25 mm Hg) or 0.6 mm Hg. The method of measurement is accurate, without limitations on driving parameters. The information is available without any additional prosthetic fabrication or surgical intervention than that already needed for basic TAH implantation. This method of measuring atrial pressures now needs to be proved effective in vivo.
Three Clinical Methods of Circulatory Assistance
Authors: Petrovsky B. V. , Kniazev M. D. , Konstantinov B. A. , Gigauri V. S. , Meluzov K. L. , Lepilin M. G. , Lokshin L. S. , Melemuka I. V. , Vasil'ev M. P.
Published: November 2008

Abstract: Three clinical methods of circulatory assistance are described: intraaortic balloon counterpulsation, left ventricular bypass using a roller pump, and the artificial ventricle. All three methods have hemodynamic effectiveness. The first method is indicated in cases of widespread cardiosclerosis and pronounced coronary insufficiency and may be contraindicated in pathology of the valvular apparatus. The second method demonstrated a temporary positive effect in patients in whom it was not possible to discontinue artificial circulation. The artificial ventricle is useful in treating patients with cardiogenic shock following cardiac surgery.
Use of an Ellipsoid Artificial Heart
Authors: Shumakov V. I. , Zimin N. K. , Drobyshev A. A. , Petukhova M. N. , Agafonov S. V. , Itkin G. P.
Published: November 2008

Abstract: Experiments with the Poisk model of an ellipsoid artificial heart are reported. With a modified model of the diaphragm type made from polyurethane, calves survived for a mean of 55 days, with a maximum survival of 3 months. With adequate anticoagulation therapy, no thrombogenesis was observed in the blood chamber (except for the inlet valves); a low level of plasma hemolysis was observed postoperatively. Good correlation was demonstrated between the stroke volume and left and right atrial pressures. Changes in the blood coagulation indices are reported. Implantation of a clinical variant of this prosthesis into human cadavers demonstrated no difficulties in placing the heart in the pericardial cavity. Developmental efforts are continuing.
Paracorporeal Assistance System for Restoring Cardiac Activity
Authors: Tolpekin V. E. , Koblov L. F. , Kuvaev A. E. , Gasanov E. K.
Published: November 2008

Abstract: Two series of experiments were conducted to assess the potential of artificial ventricular bypass in restoring cardiac activity. One series evaluated use of a paracorporeal left ventricle in 17 calves; the other evaluated biventricular bypass in 11 calves. Module pumps with a seamless blood chamber of polyurethane were used. Pump function and system parameters were controlled by a Sinus VK‐2 control system. Assisted perfusion began with the induction of ventricular fibrillation. The experiments showed that left ventricular bypass was an effective method for long‐term maintenance of the hemodynamics during fibrillation, leading to certain biochemical corrections and restored electrical activity and myocardial contractile function. The hemodynamic state was maintained at a higher level with biventricular bypass and was accompanied by a greater percentage of restored myocardial function. Uneven restoration of contractile activity in the left and right ventricles points to the need for adequate support of both ventricles.
Automatic Control Systems for the Artificial Heart and Ventricular Assist Device
Authors: Guskov I. A. , Zatiuriukin A. B. , Kuznetsov E. P. , Khanin M. A. , Antropov V. I. , Bukharov I. B.
Published: November 2008

Abstract: Automatic control systems for the artificial heart (AH) and ventricular assist device were developed using selected criteria of effectiveness, a mathematical model of regulation, and noninvasive measures of the hemodynamic parameters. The Sinus IS2 system was developed for control of the AH; its main component is a highspeed servomechanism that provides for the generation of pneumatic pulses. The servomechanism is controlled by automatic regulation with pressure feedback. Mean aortic pressure was used as the primary regulated hemodynamic parameter. The systems were tested using both a physical model and a physiologic experiment. Contractile insufficiency of the left ventricle was simulated in testing the control system for circulatory assistance. The studies demonstrate that automatic control systems function effectively by providing normal blood circulation in both the resting state and in certain transient processes occurring in a real, dynamic circulatory system.
Hypersensitivity to Hemodialysis: The United Kingdom Experience
Authors: Nicholls Anthony J.
Published: November 2008

Abstract: A postal survey of all U.K. hemodialysis centers was conducted to investigate the prevalence of hypersensitivity in the first use of disposable dialyzers. A total of 117 patients with 243 separate reactions were identified, suggesting that 1 in 20 to 1 in 50 patients may be susceptible to an anaphylactoid reaction to a new hemodialyzer at some time, while the risk of reaction occurring with any single hemodialysis is ‐1 in 1,000 to 1 in 5,000. No particular brand or type of hemodialyzer nor any identifiable technique of priming procedure was associated with reactions, but in those few patients who suffered repeated reactions further problems were avoided by increasing the volume of saline in the initial rinse of the hemodialyzer or by changing to another brand of hemodialyzer. Although it is likely that many reactions are unrecognized or unreported, the scale of the problem is larger than many British nephrologists had suspected.
Ethylene Oxide (ETO) as a Major Cause of Anaphylactoid Reactions in Dialysis (A review)
Authors: Bommer Jürgen , Ritz Eberhard
Published: November 2008

Abstract: Ethylene oxide (ETO), an alkylating compound of high chemical reactivity, is widely used for gas sterilization, but recently serious ETO side reactions have been recognized. With chronic ETO exposure, increased spontaneous abortion, sister chromatid exchange, and leukemia are observed. After medical use of ETO outside nephrology, contact dermatitis, cardiopulmonary shock (during cardiopulmonary surgery), allergic local reactions to ETO sterilized lenses, and anaphylactoid reactions to ETO sterilized catheters have been described. In numerous dialysis patients widespread hypersensitivity to ETO has been documented by skin prick test and ETO radioallergosorbent test (RAST). Furthermore an anaphylactoid “first‐use reaction” was described in dialyzed patients, most of whom were using hollow‐fiber dialyzers. After long discussions whether complement activation versus hypersensitivity is the cause of such acute anaphylactoid reactions, more recent studies using either ETO RAST or basophil degranulation tests implicate ETO hypersensitivity as their major cause. The high prevalence of sensitization to ETO and the frequency, unpredictability, and potential danger of anaphylactoid reactions to ETO lead to the conclusion that ETO sterilization of dialyzers should be discontinued, since alternative modalities of sterilization are currently available.
Influence of Reuse and of Reuse Sterilants on the First‐Use Syndrome
Authors: Vanholder Raymond , Ringoir Severin
Published: November 2008

Abstract: Over a 4 year period, five of 98 patients at our dialysis unit developed signs and symptoms consistent with first‐use syndrome (FUS). Marked improvement was noted after subjecting new dialyzers to automated processing using either formaldehyde or peracetic acid. No episodes of FUS occurred in patients being treated with reused dialyzers. Use of formaldehyde sterilization was associated with development of anti‐N‐like antibodies in the blood of four (8%) of 50 patients over a follow‐up period of 14 months. In two patients on the reuse program, itching during dialysis resolved after changing from formaldehyde‐sterilization to a method using peracetic acid. Our results confirm the beneficial effects of reuse with regard to first‐use syndrome. However, our data also suggest that use of formaldehyde, the most common reuse sterilant, continues to be associated with undesirable clinical and laboratory side effects.
Dialyzer Membranes: Effect of Surface Area and Chemical Modification of Cellulose on Complement and Platelet Activation
Authors: Mahiout A. , Meinhold H. , Kessel M. , Schulze H. , Baurmeister U.
Published: November 2008

Abstract: Using an ex vivo model, the effects of membrane composition and surface area on both the complement system (as reflected by plasma C3a levels) and platelets [as indicated by plasma concentrations of thromboxane B2 (TXB2) and platelet factor 4 (PF4)] were studied. In this model, polyacrylonitrile (PAN) was associated with less complement activation than cuprammonium cellulose (CC). A new “modified cellulose” (MC) membrane, in which a small number of the free hydroxyl groups on cellulose are substituted with a tertiary amino compound, was also associated with a low degree of complement activation, similar to that with PAN. However, the extent of hydroxyl group substitution in four MC membrane subtypes did not correlate with the reduction in complement activation. In studies using CC, the amount of generated C3a correlated with the membrane surface area, although the relationship was curvilinear. Plasma concentrations at the “dialyzer” outlet of TXB2 and PF4 were similar with CC, PAN, and MC. In studies with the MC subtypes, increasing the extent of hydroxyl group substitution paradoxically increased, albeit slightly, the amount of TXB2 generation. In studies with CC, a linear relationship between membrane surface area and TXB2 generation was found. The results suggest a dissociation between platelet and complement effects among different dialyzer membranes, and underline the importance of membrane surface area.
A Model of Ultrafiltration and Glucose Mass Transfer Kinetics in Peritoneal Dialysis
Authors: Jaffrin M. Y. , Odell R. A. , Farrell P. C.
Published: November 2008

Abstract: We have investigated the variation with dwell time of dialysate volume and glucose concentration during continuous ambulatory peritoneal dialysis using a one‐pool model. No assumption was made regarding the ultrafiltration rate that was calculated by the model. Results show that the volume ultrafiltered during dwell time is an increasing function of peritoneal membrane hydraulic permeability and a decreasing function of glucose mass transfer coefficient (MTC). For large MTC and low initial glucose concentration there is reabsorption of dialysate into the blood at large dwell times. For a 6 h dwell time, glycerol (92 daltons) is a more effective osmotic agent than glucose (198 daltons) at the same weight concentration. These results are in quantitative agreement with published clinical studies.
Liver Preservation Techniques for Transplantation
Authors: Toledo‐Pereyra Luis H. , Bergren Carl T.
Published: November 2008

Abstract: The development of optimal methods for preservation is important for the advancement of liver transplantation. This study compares hypothermic storage (HS) and hypothermic pulsatile perfusion (HPP) with various solutions, using an isolated normothermic perfusion model (LIPM). Canine livers were removed from mongrel dogs without warm ischemia and flushed with either heparinized Ringer's lactate (control and HPP‐preserved groups) or the solution used for hypothermic storage (TP‐V or modified Collins). The type of preservation and solution for each of the experimental groups was as follows: group I (n = 7), no preservation, fresh; group II (n = 7), 24‐h HS with TP‐V (a hyperosmolar colloid solution containing sucrose, dextrose, and ATP‐MgCl2); group III (n = 7), 24‐h HS with modified Collins (C‐2), an intracellular crystalloid solution; group IV (n = 5), 24‐h HP with TP‐V; group V (n = 6), 24‐h HPP with Belzer solution, containing ATP‐MgCl2; group VI (n = 3), 24‐h HPP with albumin. After the preservation period, livers were placed on HPP at 37°C with albumin‐mannitol solution for 3‐h testing in an LIPM. Perfusate samples were taken at 1‐h intervals to assess liver function. LDH, SGOT, alkaline phosphatase, lactic acid, LAP, GGT, pO2, pCO2, pH, osmolarity, AMP, ADP, and ATP were studied. Histologic studies were performed, as were representative HIDA scans. Using the LIPM, livers preserved by HS and HPP with TP‐V solution appeared to be superior to those preserved with modified Collins, Belzer, and albumin solutions. In these non‐TP‐V groups, the greatest cellular and organ damage was observed. TP‐V HPP appeared to give the best overall liver functional response and histologic results and is recommended as the preferred method for 24‐h liver preservation.
Platelet Adhesion and Prevention at Blood‐Polymer Interface
Authors: Kim Sung Wan
Published: November 2008

Abstract: It has been proposed that adsorbed glycoproteins such as fibrinogen and γ‐globulin induce platelet adhesion at blood‐polymer interfaces. The importance of oligosaccharide groups in the glycoproteins proved to be responsible for platelet adhesion and aggregation via possible complex formation. Several studies have provided evidence that the proposed mechanism was involved in platelet adhesion on polymer surfaces. To minimize or prevent platelet adhesion on polymers, prostaglandins (PGs), potent inhibitors of platelet aggregation and PG‐heparin (HEP) conjugate, were combined with polymers via physical dispersion or chemical immobilization on the surfaces. Albumin‐HEP conjugate‐adsorbed surfaces also showed significant reduction of platelet adhesion.
Implantable Ventricular Assist Systems
Authors: Altieri Frank D. , Watson John T.
Published: November 2008

Abstract: A major goal of the Circulatory Support Program of the National Heart, Lung, and Blood Institute (NHLBI) is the development of a tether‐free implantable ventricular assist system (VAS) to rehabilitate patients with advanced heart disease. In 1980, the NHLBI initiated a targeted program to develop and integrate implantable electromechanically powered VASs capable of operating for at least 2 years. The objectives of the program are to complete the development of the VAS and perform in vitro and in vivo evaluation studies. This article summarizes the research status of this NHLBI‐sponsored program. It defines the VAS system requirements, describes the systems under development, identifies progress achieved to date, and identifies research challenges.
A Technique for Apex Cannulation without Extracorporeal Circulation
Authors: Fujimoto Luiz K. , Nosé Yukihiko
Published: November 2008

Abstract: A simple, fast, and highly reliable technique for apex cannulation without extracorporeal circulation is presented as a result of more than 30 left ventricle assist device implants performed in calves in the last 4 years at the Cleveland Clinic Foundation. Minimal bleeding and reduced risk of ventricular fibrillation, air emboli, muscle flap, and trauma to the heart have made this technique very unique and highly applicable to any investigative laboratory, as no special tools or expensive apparatus are required. The practicality of the technique is immediately applicable to the clinical level to avoid potential complications with cannula insertion.
In Vitro Development of Automatic Control for the Actively Filled Electrohydraulic Heart
Authors: Lioi Anthony P. , Orth Jeffrey L. , Crump Kevin R. , Diffee Glenn , Dew Pamela A. , Nielsen Steve D. , Olsen Don B.
Published: November 2008

Abstract: The in vitro development of automatic control of the actively filled, alternately pumped, volumetrically coupled, electrohydraulic total artificial heart was the goal of this investigation. Control features under study were (a) cardiac output (CO) response to preload; (b) CO relationship to mean aortic pressure (AoP); and (c) control of balanced ventricular outputs. A modified pulmonic valve to increase backflow was used as a balancing mechanism. Hydraulic fluid pressure transducers monitored diastolic pressures, and microprocessor control of motor speed maintained in a mild suction to yield filling rate dependent on atrial pressure. Results indicated a rise in CO from 5 to 9L/min, with a change in mean right atrial pressure (RAP) from 0 to 7mm Hg. No significant difference in CO was found as AoP was varied from 80 to 120mm Hg with a maximum variation of ±0.5 L/min on CO and ±1mm Hg on RAP. Balance was maintained for bronchial flows up to 5% with mean left atrial pressure never exceeding 15mm Hg. An alternately pumped electrohydraulic heart was automatically controlled to respond sensitively to preload changes. Afterload changes did not alter the CO response curve. Automatically controlled, balanced ventricular outputs were maintained.
Definitions of Differences and Changes in Peritoneal Membrane Water Transport Properties
Authors: Widerøe Tor‐Erik , Smeby Leif C. , Dahl Ketil , Jörstad Störker
Published: November 2008

Abstract: A survey is given comparing measurements of transperitoneal water transport in different clinical situations with analyses based on the so‐called “pore theory.“ This model links the measured changes to physical alterations of the peritoneal membrane. The calculations include “equivalent pore radius,“ effective “membrane area“ and diffusive length, the transport resistance of the unstirred dialysate layer, and the residual intraperitoneal volume after dialysate drainage. The clinical appearances include individual differences in transperitoneal transport characteristics, changes in transperitoneal transport over time on continuous ambulatory peritoneal dialysis (CAPD) and during peritonitis, the pharmacological effect on the transport properties, and the effect of peritoneal catheter dislocation on ultrafiltration capacity. The main conclusions are as follow: During CAPD treatment the measurement of intraperitoneal solute equilibration and “mass‐transfer‐area coefficients“ for urea and creatinine is less sensitive than the measurement of ultrafiltration volume in revealing peritoneal membrane changes. Differences and changes found have mostly a combined physical explanation, but one is more or less dominant. Changes in peritoneal membrane area seem to be the most dominant cause of changes in transperitoneal transport during time on CAPD and when sodium nitroprus‐side was added to the peritoneal dialysate. Changes during peritonitis can be explained by changes in pore radius and depth. Individual differences can be explained by differences in “membrane“ area and in resistance of the unstirred dialysate fluid. High residual dialysate volume can give rise to clinical problems and should be considered when placing the catheter in the peritoneal cavity.
Effect of Blood Purification on the Kidney Function of the Jaundiced Rat
Authors: Koyama Kenji , Asanuma Yoshihiro , Fukaya Hisami , Omokawa Susumu
Published: November 2008

Abstract: This paper is aimed at evaluating the effect of blood purification on the mitochondrial functions of the kidney in jaundiced rats. At 1, 2, or 3 weeks after bile duct ligation and dissection, obstructive jaundiced rats were utilized for experiment. Cross circulation in 1 ml/min between jaundiced rats and normal rats was performed for 1 or 3 h. Immediately and 24 h after cross circulation, the rats were killed and mitochondrial respiratory functions of the kidney were assessed by measuring oxygen consumption. Mitochondrial function, especially ATP synthesis, showed significant improvement in jaundiced rat with 2 or 3 weeks of biliary obstruction. Cross circulation for 3 h was more effective than that for 1 h. These data suggest that the renal energy production can be increased significantly in obstructive jaundice by blood purification treatment.
Therapeutic Effect of Plasma Exchange with the Biliary Drainage in the Treatment of Obstructive Jaundice
Authors: Ohyanagi Harumasa , Usami Makoto , Kimata Hiroki , Saitoh Yoichi
Published: November 2008

Abstract:The effect of therapeutic plasmapheresis combined with biliary drainage was evaluated in obstructive jaundice animal models. Plasma exchange (PE) using fresh‐frozen plasma was carried out with biliary drainage (BD) on a canine jaundice model created by the ligation and resection of bile duct. Routine biochemical analyses were done following PE and BD. The result was compared with that of a BD only group. Plasma bilirubin level abruptly dropped after PE and was kept at a lower level, whereas the bilirubin level of the drainage alone group decreased gradually. Decreased plasma mitochondrial GOT level in the PE group suggests improvement of liver cell damage in obstructive jaundice. Mitochondrial function of liver tissue was evaluated following partial hepa‐tectomy, which was carried out 2 days after PE along with BD in jaundice rat. Mitochondrial respiratory control ratio and ADP/O ratio following hepatectomy were improved in the PE group. The results suggest the improvement of hepatic functional reservoir by a single PE treatment in addition to BD treatment. These results show that PE can shorten the icteric period and may improve the hepatic functions after the treatment of malignant obstructive lesion in the biliary tract.
Development of the Philadelphia Heart System
Authors: Wurzel D. , Kolff J. , Missfeldt W. , Wildevuur W. , Hansen G. , Brownstein L. , Riebman J. , de Paulis R. , Kolff W. J.
Published: November 2008

Abstract: A new pneumatic artificial heart system has been developed. The design criteria have been to produce an integrated series of blood pumps and drive systems that would reduce blood trauma and reactivity, while incorporating industrial, mass‐production techniques. The system attempts to reproduce the natural heart's pressure and flow waveforms and allows the prosthetic valves to be installed in a manner consistent with their design. The system's ventricles are constructed entirely of polyure‐thane by a combination of vacuum‐forming and solution‐casting techniques. The atrial cuffs and arterial grafts are permanently attached to the pumps and do not incorporate a quick connect system. The prosthetic valves are sewn into the inflow and outflow tracts using their clinical sewing rings. Besides eliminating the crevices normally found in quick connect systems, this method mounts the valves in an extremely compliant housing to increase shock absorption. The drive system produces a systolic air flow with a variable pressure rise (dP/dt) to reduce mitral valve closing velocity. This system has been implanted into 25 calves to date, of which 17 were chronic experiments. In 14 animals, St. Jude bileaflet valves were used and these animals had a mean survival of 39 days. Six of these animals survived over 30 days, with the longest being 129 days. All of the animals showed the characteristic postoperative drop in red blood cell count and hematocrit that returned to near preoperative values in about 3 weeks. The plasma free hemoglobin values generally remained below 5 mg/dl. The necropsies performed on several of the earlier animals revealed renal infarcts. However, in two of the later experiments, no kidney damage was found. The blood contacting surfaces of the atrial cuffs from the animals surviving over 100 days were covered with a fibroprolif‐erative pseudoneointimal growth that extended from the sewing rings to the natural atrial tissue. Grossly, this appears to be the same type of tissue response seen when only a valve is implanted in a natural calf heart.
New Membrane for Cell Encapsulation
Authors: Tatarkiewicz Krystyna
Published: November 2008

Abstract: A new membrane for microencapsulation of Langerhans islets is proposed. To obtain good biocompatibility properties, the membrane is prepared from polyethyleneimine, with heparin and protamine sulfate added. Investigation of the permeability of the membrane was based on Fick's law of the diffusion into and out of a sphere. It was observed that glucose and insulin easily diffuse into and out of microcapsules. Membrane itself is not permeable for human albumin and γ‐globulins.
Characterization and Identification of Substances Isolated from Dialyzer Extracts
Authors: Postaire Eric , Cohen Jean‐Michel , Paul Jean‐Louis , Fournier Gilles , Corvazier Michéle , Jehenne Guillaume , Raichvarg Denis , Man Nguyen‐Khoa
Published: November 2008

Abstract: The organic phase of dialyzer dried extracts obtained from Cuprophan hollow fiber and polyacrylonitrile AN 69 parallel‐plate dialyzers, all sterilized by ethylene oxide, were submitted to light and polarized light microscopy, infrared (IR) spectrophotometry, and gas chromatography coupled with mass spectrometry. Colorless polygonal (˜5 times 20 μ.m) and needle‐like (˜3 times 50 μm) crystals were found in great quantity on microscopy examination. IR spectrophotometry of the crystals embedded in potassium bromide disc showed specific spectra in the 1400‐800 cm‐1 wave number range and typical peaks on wave number assigned for hydroxy or amine (3420 cm‐1), aromatic hydrogen (3060 cm‐1), methyl, methyl‐enic, or methenyl (2960‐2860 cm‐1), and carbonyl (1715 cm‐1) groups can be demonstrated. Seven peaks were detected on gas chromatography of the organic solution containing crystals. Fatty acids and undefined compounds could originate from the dialyzer. Phtalates may leach from blood tubing, used in the rinsing procedure, and BHT is a stabilizer of ethyl ether used as solvent. These compounds could also originate from the dialyzer since phtalates are widely used as a plasticizer and BHT an antioxidant for various polymers.
Continuous Computerized Monitoring of Hemodynamic Parameters during Acetate Dialysis, Bicarbonate Dialysis, and Acetate‐Free Biofiltration
Authors: Spongano Marco , Santoro Antonio , Ferrari Giuseppe , Badiali Fabio , Rossi Marco , Parrino Andrea , Lamberti Claudio , Sardi Eugenio , Zucchelli Pietro
Published: November 2008

Abstract: The effects of continuous, computerized, noninvasive hemodynamic monitoring on the appearance of intradialytic symptoms, aided by preventive therapeutic maneuvers, were evaluated in 30 critically ill patients undergoing regular acetate dialysis. The hemodynamic behavior was assessed by a system that interfaces a personal computer with a blood pressure monitor and to a transthoracic electrical impedance‐measuring instrument. Monitoring allowed us to reduce significantly the frequency of some important intradialytic symptoms such as nausea, vomiting, and hypotension. The same monitoring system was used acutely to characterize differing hemodynamic behaviors during acetate dialysis (AD), bicarbonate dialysis (BD), and acetate‐free biofiltration (AFBF). AD showed a prevalent vasodilation effect with a compensatory increase in heart rate and higher cardiac output values, which were not sufficient to maintain blood pressure stability. BD and AFBF were characterized by a more efficient vasoconstrictor effect and good hemodynamic stability. AFBF, despite a 1 h reduction in session length compared to BD, did not present significant differences in hemodynamic response resulting from session shortness or other technical changes.
Surface Modification for Improved Blood Compatibility
Authors: Jacobs H. , Grainger D. , Okano T. , Kim S. W.
Published: November 2008

Abstract: : Several surface modification techniques are currently being used to improve the biocompatibility of blood‐contacting devices. These include the immobilization of bioactive materials to prevent thrombus generation and platelet activation, the incorporation of hydrophilic grafts onto practical hydrophobic surfaces (polyurethanes) to reduce protein adsorption, and the concept of microdomain‐phase separated surfaces to regulate cellular and protein adhesion.
Transport and Kinetics in Synthetic and Immunospecific Adsorption Columns
Authors: Schindhelm Klaus
Published: November 2008

Abstract: Immunological or physicochemical adsorption can be used to remove specific proteins from plasma. The most common adsorption systems are based on the principle of affinity or adsorption chromatography. An adsorption column can be considered to be analogous to a packed bed, and transport is modeled by accounting for solute convection, accumulation, uptake, and axial dispersion within the bed. Adsorption kinetics and transport within particles of the packed bed need to be described. The solution of model equations is solute specific and generally requires numerical methods. The application of column adsorption systems to on‐line therapeutic adsorption is constrained by flow considerations, which influence processing time; adsorbent capacity, which dictates column volume and hence design; and adsorbent stability, which may impact on patient safety.
Surface Area Effects on Efficiency and Biocompatibility in Experimental Membrane Plasmapheresis
Authors: Omokawa Susumu , Malchesky Paul S. , Suzuki Toshiaki , Uchida Naoki , Nosé Yukihiko
Published: November 2008

Abstract: The effect of different surface areas on cellular, humoral, and hemodynamic changes and on plasma separation performance were investigated. Membrane plasmapheresis, consisting of plasma separation and on‐line reinfusion, was carried out on dogs for 3 h with 0.6 and 0.3‐m2 polyethylene (PE) and polyvinyl alcohol (PVA) modules. The plasma separation and sieving performance was comparable in both the 0.6 and 0.3‐m2 modules. The initial white blood count (WBC) reductions were independent of the surface area difference, but the rebound was greater in the smaller modules. The platelet (PLT) reductions were less with the 0.3‐m2 PE module in comparison to those with the larger PE module, but no differences existed between both of the PVA modules. The smaller PVA module showed less complement activation compared to the 0.6‐m2 module, whereas both of the PE modules showed comparable changes. Hemodynamic responses, especially the changes in pulmonary vascular resistance, were less with the smaller modules compared to the 0.6‐m2 modules. The PE modules themselves showed less blood cellular, humoral, and hemodynamic changes compared to the PVA modules. The smaller modules showed greater rebound of WBC counts, however, PLT reductions, complement activation, and changes in hemodynamic parameters were less in the smaller modules.
Extracochlear Electrical Stimulation
Authors: Aronson Leonora , Arauz Santiago Luis , DeCorvetto Amalia Shinjo , de Zaccaria Silvia Natalia Mastroianni Pinto , Pallante Alfredo Samuel , Zanutto Silvano Bonifacio
Published: November 2008

Abstract: Twelve patients with sensorineural hearing loss were stimulated by a transtympanic electrode contacting the cochlear promontory. Nine of them were tested to study hearing perception associated with various features of electrical signals, using an auditory electrical stimulator. Biphasic pulse bursts and sine‐wave bursts were used as stimuli. Different electrical characteristics such as amplitude, width and rate for pulses and amplitude and frequency for sine waves were used to investigate hearing perception. The patients' perception threshold, comfortable level, uncomfortable level, dynamic range, just‐noticeable difference in frequency or pitch discrimination, just‐noticeable difference in intensity or loudness discrimination, loudness perception associated with the electrical signal energy, and sounds associated with electrical stimulation was determined. Pertinent results assisted in the development of a speech electrical stimulator that was used to test three patients for vowel, word, and consonant identification and recognition of patterns of intonation. These results in turn are being used to design a prototype of a single‐channel extracochlear prosthesis.
The Realization of a Pulsatile Implantable Impeller Pump with Low Hemolysis
Authors: Qian K. X. , Fei Q. , Lin K. D. , Pi K. D. , Wang Y. P.
Published: November 2008

Abstract: A pulsatile implantable impeller pump with low hemolysis was developed without markedly increasing the complexity of the system compared with the nonpulsatile pump. The key to the question is to design a three‐dimensional impeller with twisted vanes, compacted by an axial helical spiral and a radial logarithmic spiral so as to reduce the turbulent shear in the pump as the impeller changes its rotations per minute periodically to generate a physiologic pulsatile flow. Both mathematic computation of velocity distribution in the impeller and geometric illustration of the velocity triangle at the top of the vane have demonstrated that the peripheral velocity variation of blood cells in a twisted impeller will be less than that in an untwisted impeller. Thus, the main mechanical factor of hemolysis in the impeller pump, namely, the turbulent shear, should be reduced because it is proportional to the product of velocity variations measured in two perpendicular directions. In the in vitro experiments, the pump delivered 4 L/min mean flow at 100 mm Hg mean pressure (pulsed between 80‐120 mm Hg) for more than 3 h in a circulatory model containing 700 ml of fresh citrated porcine blood. Every half hour, the free hemoglobin level in the plasma was tested, and the resulting index of hemolysis was about 0.020, slightly more than that of a nonpulsatile impeller pump developed in Shanghai. To compare hemolyses, the index of hemolysis of this pump is about !4 of that of the self‐made diaphragm pump and Va of that of the Polystan Pulsatile Pump. In the in vivo evaluations with dogs and goats, the pump was used as a left ventricular assistance device. The bypass ratio in all cases was adjusted to 40‐50% of the total flow. Approximately 30‐mm Hg reduction of left ventricular pressure and a 10% decrease of pressure rising rate were observed by asynchronous perfusion. The blood count and hematocrit reading of experimental animals decreased unremarkably during the survival time for up to 21 h, and the free hemoglobin level in the plasma remained under 50 mg/dl. The output of the pump was controlled by adjusting the mean voltage, and the pulsatile frequency has no effect on mean flow. The pump weighs 250 g (including a 190‐g motor).
Effect of Hemodialysis on T Lymphocyte Subsets, Con‐A‐Activated Suppressor Cell Activity, and Interleukin‐2 Receptor Expression on Lymphocytes in Chronic Uremic Patients
Authors: Tchórzewski Henryk , Luciak Marek , Trznadel Kazimierz , Majewska Ewa , Pokoca Lech
Published: November 2008

Abstract: Effect of hemodialysis (HD) on some indices of immune response was studied in nine chronic uremics. Total lymphocyte, OKT4 +, and OKT8+ cell numbers significantly decreased during the first 20 min of HD, and they were decreased till the third hour of the procedure, whereas the OKT4 +/OKT8 + cell number ratio did not change significantly. Before HD, Con‐A‐activated suppressor cells exerted a stimulatory action on autologous responder cells measured in two‐step culture. During HD, Con‐A‐activated suppressor cell activity transiently appeared, with its peak at 60 min after the start of HD. It was accompanied by a transient rise in lymphocyte count with spontaneous interleukin‐2 (IL‐2) receptor expression, whereas the number of cells expressing IL‐2 receptor following phytohemaglutinin (PHA) stimulation was progressively decreased during HD. A significant correlation was found between the increment of Con‐A‐activated suppressor cell activity and the increment of spontaneous IL‐2 receptor expression on lymphocytes during one single blood flow through the dialyzer. The results supply further evidence that HD may impose additional disturbances on immune regulation in chronic uremics.