bluuebunny/crossref_metadata_2025 huggingface dataset:
Dialysate Sodium Control During Modeling in Hemodialysis
Authors: Ragon A. , Reynier J. P. , Murisasco A. , Elsen R. , Leblond G.
Published: November 2008

Abstract: Dialysate sodium (Na+) modeling in hemodialysis requires precise individual adjustment and control of Na+ dialysate concentration. In practice, variations of Na+ concentration can be important and can affect the accuracy of Na+ modeling. Variations relate mainly to the low accuracy of dialysate concentrate (±2.5% for Na+ is tolerated by the European Pharmacopeias), purity of hemodialysis water (2.17 mEq/L is the limit fixed by the French Pharmacopeia), and precision of the proportioning delivery systems for hemodialysis bath preparation. To minimize these difficulties, this study focused on the following points: (a) Na+ concentration is maintained constant (133 mEq/L) in the dialysate manufacturing unit. In 1982, 268 dialysate preparations (177,000 L) were made, and the mean value for Na+ concentration was 133.1 ± 0.3 mEq/L with a probability of 99.9%. (b) The purity of the water, especially for Na+, Ca2+, and K+, is controlled for two times a day. (c) The accuracy of the proportioning delivery system is controlled by two conductivity monitors, and the variation of Na+ concentration around 133 mEq/L is smaller than ±0.5%. As the composition of the basic dialyzing fluid remains constant before adaptation, conductivity values reflect exactly Na+ variation, and are not affected by variations of other elements (K+, Ca2+, Mg2+) that may occur when modification of the dialysate is used for Na+ modeling, (d) Na+ dialysate concentration is adapted for each patient's need by a bedside monitor with sterile Na+ solutions (5 mol/L). The additional pumps are calibrated with precision and increase gradually the Na+ dialysate concentration from 0.7 to 14 mEq/L. Two pumps can be used simultaneously. Dialyzing fluid is also adjusted for K+ and Ca2+ with the same system. This method allows an accurate adjustment of Na+ concentration (±1%) without interference of the other elements and permits Na+ modeling for 64 patients each day. A precision of 1% or even less for Na+ concentration in the dialysate bath can be obtained in routine use, provided that special attention is focused on some parameters for the accuracy and reliability of concentration measurements. The precision of Na+ concentration in the concentrate is also of great importance, and it appears that if modeling in the future becomes widely used, a reduction of the norms required by the pharmacopeias will be necessary.
What Are the Ethical and Social Implications of Artificial Organs?
Authors: Cortesini R.
Published: November 2008

Let me introduce some basic principles and fundamental justifications for our moral attitude in medicine before discussing the problems of artificial organs. It is clear that the enormous increase of power in the hands of doctors raises many questions that have never previously been posed. “Science has made us gods before we are even worthy of being men” (1). Such an acquisition of power would demand a “supplément d‘âme,” as Pope John Paul II said, which we are not sure of possessing.
Cardiac Pacing in Japan
Authors: Iwa Takashi
Published: November 2008

Abstract: A general update on pacemakers and cardiac pacing in Japan in 1981 is presented, including costs, pre‐pacing studies, follow‐up, pacing center activity, average number of first implants per million inhabitants, age of patients at first implantation, clinical indications for pacing, etiology, prepacing electrocardiogram, pacemaker hardware, electrode leads, electrocardiogram indications for pacing, indications for generator or electrode changes, and extended application of pacing. The author's data are compared with those obtained by the survey of the Seventh World Symposium on Cardiac Pacing.
Resin Hemoperfusion in Hepatic Porphyrias
Authors: Horák Jiří , Martásek Pavel , Kordač Václav , Mertl Ladislav , Jirsa Milan , Tlusťáková Marie , Houštková Hana
Published: November 2008

Abstract: In three types of hepatic porphyrias, 32 hemoperfusions over polyhema‐coated Amberlite XAD‐2 resin were performed. An attack of acute intermittent porphyria subsided after a 6‐h hemoperfusion. During the procedure, 13 L of plasma was completely cleared of porphyrins. In a child with variegate porphyria, the laboratory changes were slight and no clinical effect of hemoperfusion was seen. In a patient suffering from porphyria cutanea tarda resistant to standard therapy, 30 hemoperfusions were performed during a period of 10 months. The total plasma porphyrin concentration increased sharply following the start of the treatment, and preceding the fifth procedure it reached a peak of four times the initial value. Since then, the plasma porphyrin level decreased, eventually to one‐half the starting value. The mean drop in porphyrin level during each perfusion was 22%. Similar changes were observed in the amount of porphyrins excreted into the urine, which, following an early rise, decreased to 25% of the initial value. However, the patient's skin vulnerability improved only slightly. There were no untoward effects of the treatment.
Temporary Vascular Access in British Hemodialysis Units
Authors: Tapson John Stephen
Published: November 2008

Abstract: A questionnaire, designed to determine the current habits of British nephrologists regarding temporary vascular access for hemodialysis, was sent to 62 renal units. Forty‐six (74%) completed questionnaires were returned. Cannulation of the subclavian vein with a single‐lumen catheter is the most popular technique. There is only limited use of double‐ or dual‐lumen catheters in the United Kingdom. Previously unreported fatal complications of subclavian hemodialysis catheters are described.
Fluid Volume Changes During Hemodialysis Monitored with the Impedance Technique
Authors: Tedner B. , Lins L. E.
Published: November 2008

Abstract: A fluid monitor based on the tetrapolar impedance technique was employed for continuous measurements of fluid volume change during hemodialysis treatment and compared to concomitant ultrafiltration and bed scale readings. Oral fluid intake before and during the dialysis immediately could be recorded with the bed scale as a weight change. In the readings of the fluid monitor, however, the response to fluid intake could be recorded only gradually, as the fluid was absorbed from the gastrointestinal tract. Taking this into account, together with a previously described artifact due to shifts in body position, an excellent agreement was obtained between impedance and bed scale fluid volume monitoring. It is concluded that impedance measurements give a better estimation of the amount of metabolically active fluid than does body weight monitoring.
Canine Islets in an Ultrafiltered Environment
Authors: Merrell Ronald C. , Basadonna Giacomo
Published: November 2008

Abstract: Molecular sieve membranes can protect pancreatic islets against immune recognition in diabetic patients treated by endocrine tissue replacement. These biocompatible membranes permit the passage of small peptides such as insulin, and preclude the diffusion of immunoglobulins and immunogenic molecules. However, the tissue must function indefinitely in an ultrafiltered environment determined by the sequestering membranes. The chronic perifusion of canine islet tissue was compared in ultrafiltered and microfiltered chambers. The biphasic pattern of insulin release by similar numbers of islets from the same pancreas preparation was not significantly different when tissue was cultured in a micro or an ultrafiltered environment. The cumulative insulin output of the two systems was quite similar over 3 days of culture. Canine islet tissue can be sustained in an ultrafiltered environment with maintenance of insulin release to glucose stimulation, which is quantitatively similar to islet tissue maintained in chronic perifusion without ultrafiltration.
Membrane Plasma Separation Through Small‐Area, Hollow‐Fiber Filters
Authors: Gupta B. B. , Jaffrin M. Y. , Ding L. H. , Dohi T.
Published: November 2008

Abstract: The filtration capabilities of small polypropylene hollow‐fiber plasma filters with membrane areas ranging from 100 to 1,000 cm2 have been investigated. It is found that the filtration flux per unit membrane area is approximately proportional to the wall shear rate γw at least up to γw= 7,500 s‐1. As a result, the total filtration flow rate increases very little when the number of fibers is increased as the increase in membrane area is offset by the decrease in shear rate, but it increases with the fiber length L as L2/3. Hemolysis occurs when the transmembrane pressure exceeds a certain threshold, but this threshold is itself an increasing function of shear rate. As a result, it is possible to circulate high blood flow rates even in very small filters (100 cm2) without hemolysis, provided the fiber length is below a critical value.
Danger of an Unnecessarily Prolonged Dialysis Session: Carpal Tunnel Syndrome
Authors: Cambi Vincenzo , Nizzoli Massimo , Paganelli Enrico , David Salvatore , Bono Fabio
Published: November 2008

Abstract: Ten patients of a population of 319 on chronic intermittent treatment with Cuprophan dialyzers have undergone surgery for carpal tunnel syndrome (CTS). Since 1971 the dialysis schedule for all patients has been 4 m2/h three times per week. All patients were anuric. The operated patients represent 16% of the total population. In comparison with a dialysis population in other units described in the literature (12), 8 m2/h performed three times per week, with similar dialysis aging and a CTS incidence of 47%, it appears that the duration of the dialysis session per se increases the frequency of CTS and leads to the problem of the consequences of blood membrane interaction.
Theoretical Studies on Self‐Regulating Insulin Delivery System
Authors: Shettigar Udipi R.
Published: November 2008

Abstract: A theoretical analysis of a self‐regulating insulin delivery (SRID) system was made using published in vitro results. The SRID system consists of an encapsulated glycosylated insulin bound to concanavalin A (conA) that exchanges insulin with glucose through a reversible chemical reaction between glucose and conA‐insulin (C‐I). The mathematical analysis of the in vitro results gave the values of the forward and reverse reaction rate constants. Using these calculated reaction rate constants, the insulin release rate was predicted from a SRID cylindrical pouch in response to a change in glucose concentration. The insulin release rate was found to be strongly affected by the diffusivity coefficients of insulin and glucose within the pouch, the radius of the pouch, membrane permeability, C‐I concentration, and the kinetic rate constants. This mathematical analysis provides useful guidelines for the rational design of the SRID system.
Segmental Uterine Horn Replacement in the Rat Using a Biodegradable Microporous Synthetic Tube
Authors: Jonkman Marcel F. , Kauer Frank M. , Nieuwenhuis Paul , Molenaar Izaäk
Published: November 2008

Abstract: To investigate the possible use of a biodegradable microporous synthetic tube for fallopian tube replacement, polyetherurethane/poly‐L‐lactide (PU/PLLA) grafts in the uterine horn of the rat were studied and their patency and healing characteristics compared with those of nonbiodegradable polytetrafluoroethylene (PTFE; Teflon) grafts as well as with those of reanastomosed uterine horns. Regarding the healing characteristics, the PU/PLLA grafts were superior to the PTFE graft, as was indicated by the regeneration of endometrium and the extensive perigraft tissue ingrowth. However, the graft/uterine anastomoses of the PU/PLLA and PTFE grafts became obstructed by a plug of mucosal folds, all reanastomosed, uterine horns in the control experiments remaining open. In conclusion, although biodegradable microporous PU/PLLA uterine horn grafts have better healing characteristics than PTFE grafts, they easily obstruct at the graft/uterine junction. Mucosal suturing and/or the use of splints may contribute to the feasibility of biodegradable microporous artificial fallopian tubes in tubal surgery.
Fatigue and Hemocompatibility of Polymer Materials
Authors: Sevastianov V. I. , Parfeev V. M.
Published: November 2008

Abstract: Hemocompatibility and sufficient fatigue life of biomaterials are critical in the development of artificial hearts and circulatory assist devices. In this study, three segmented polyurethanes (PUs) were compared with a fourth PU (Czech PU) and the organosilicone rubber RKM to determine the interrelationships between type of synthetic polymer, degree of structural change in cyclic loading, and hemocompatibility. Uniaxial and biaxial static strain tests were conducted. Accelerated fatigue tests were used to predict the behavior of the materials in vivo. Damage from fatigue was assessed by light transmission and light scattering methods, and the number of adhering platelets and degree of morphological change in the platelets were compared between initial and fatigued materials. The relative index of platelet adhesion and the relative form factor were also obtained. The elasticity characteristics of the PUs were shown to be substantially greater than those of RKM. RKM required reinforcement. Czech PU was shown to have good mechanical characteristics (with high elasticity and low creep). The morphology of the cells after cyclic load changed insignificantly, whereas the number of adherent platelets increased in all cases.
Antibody Responses to Hemodialysis‐Related Antigens in Chronic Hemodialysis Patients
Authors: Dolovich Jerry , Evans Susan , Baurmeister Ulrich , Schulze Helmut , Ali Mohammed , Shimizu Arthur
Published: November 2008

Abstract: Allergic‐type reactions during hemodialysis are sometimes due to sensitization to ethylene oxide. To examine the possibility that additional antigens might be a basis for unexplained reactions, antibodies to formaldehyde and phthalte‐related antigens and to dialyzer extracts were measured. Unselected sera from 113 chronic hemodialysis patients (CHP) and 200 control subjects were tested for IgG antibodies to formaldehyde‐treated human serum albumin (HSA). The IgG antibody activity was confirmed in sera of five CHP who had used formaldehyde‐treated dialyzers. These antibodies also reacted with formaldehyde‐treated red blood cells. Sera from 71 CHP and 80 controls were tested for IgE antibodies to diethylphthalate‐treated HSA; antibody was detected in two CHP sera. With extracts from hollow‐fiber dialyzers, IgG antibody was detected in ˜1/3 and IgM antibodies in ˜1/2 of CHP sera. This antibody was found in comparable numbers of control sera. It was concluded that these additional substances are immunogenic and could be involved in allergic‐type reactions.
Mediation of Hypersensitivity Reactions During Hemodialysis by IgE Antibodies Against Ethylene Oxide
Authors: Lemke Horst‐Dieter
Published: November 2008

Abstract: Sera from 329 hemodialysis patients, 46 of whom had experienced a hypersensitivity‐type reaction during hemodialysis, were screened by an enzyme‐allergosorbent test (EAST) for IgE antibodies specific for ethylene oxide (ETO). In seven of nine patients who had experienced a severe hypersensitivity reaction (type II or type III), high titers of IgE antibodies against ETO (> 3.0 PRU/mL) were found. However, plasma levels of IgE specific for ETO were in the normal range (< 0.35 PRU/mL) in most (30/37) patients who had experienced a mild (type I) reaction. Selected sera from patients who had experienced severe reactions were further examined for IgE directed against isopropyl myristate (IPM), 2‐chloroethanol, and extracts from unsterilized dialyzers. Importantly elevated serum levels of specific IgE against these substances could not be documented. Extracts of an ETO‐sterilized, hollow‐fiber dialyzer were positive, whereas extracts of an ETO‐sterilized dialyzer containing a flat membrane were negative in the EAST. This difference can be explained by the different amounts of ETO present in the dialyzers. We conclude that ETO causes most severe hypersensitivity reactions by an IgE‐mediated mechanism. On the other hand, the pathogenesis of mild (type I) reactions is less clearly associated with ETO allergy. Our results also suggest that other potentially allergenic substances in dialyzers (e.g., IPM, 2‐chloroethanol) rarely induce specific IgE antibodies in dialysis patients.
Effect of Dialyzer Reprocessing Methods on Complement Activation and Hemodialyzer‐Related Symptoms
Authors: Dumler Francis , Zasuwa Gerard , Levin Nathan W.
Published: November 2008

Abstract: The effects of different dialyzer processing methods and of reuse on complement activation and dialyzer‐related symptoms were studied in 96 maintenance hemodialysis patients. New dialyzers were either unprocessed (Group 1) or machine‐washed with bleach and stored in formaldehyde (Group 2). Reused dialyzers were manually cleansed using the combination of bleach and formaldehyde (Group 3), or machine‐washed in formaldehyde (Group 4) or peracetic acid (Group 5). Prewashed new dialyzers (Group 2) were associated with greater complement activation during dialysis when compared with unprocessed, new dialyzers (Group 1) (p < 0.05). Reused, unbleached but formaldehyde‐treated or peracetic acid‐treated dialyzers (Groups 4 and 5) were associated with reduced complement activation (p < 0.05). Complement activation was not reduced when bleach was used for reprocessing (Group 3). The percentage of patients without symptoms during dialysis was significantly greater with reused dialyzers than with new dialyzers (Groups 3 through 5 versus Groups 1 and 2; 39 versus 25%; p = 0.035). The severity of total symptoms correlated significantly (p = 0.0004) with complement activation. Our results suggest that total symptoms during dialysis are correlated with the degree of complement activation. However, trends in the data pertaining to chest pain suggest that factors other than complement activation may be important in the pathogenesis of some dialyzer‐related symptoms.
Complement Activation During Hemodialysis: Laboratory Evaluation of Hemodialyzers
Authors: Chenoweth Dennis E. , Henderson Lee W.
Published: November 2008

Abstract: A laboratory method that facilitates delineation of the complement‐activating characteristics of various dialyzers under defined conditions has been developed. Results obtained by circulating reconstituted human serum through these devices and measuring time‐dependent production of both C3a and C5a antigens are entirely consistent with previous clinical observations. For example, the complement‐activating potential of dialyzer membranes could be described as high (cuprammonium cellulose), moderate (cellulose acetate), or low (polycarbonate or polyacrylonitrile). Furthermore, these techniques provided the opportunity to identify membrane characteristics that are not readily defined by clinical studies alone. Specifically, membranes that transported and adsorbed C5a antigen were readily identified by these methods. Additionally, laboratory evaluation provided the unique ability to define the efficiency of complement activation taking place on the membrane surface. Results of these investigations are compatible with a hypothetical model that not only describes the properties of a typical dialyzer membrane but may be generally applicable to other biomaterials as well.
Venovenous Extracorporeal Membrane Oxygenation (ECMO) Using a Double‐Lumen Cannula
Authors: Andrews Alice French , Zwischenberger Joseph B. , Cilley Robert E. , Drake Kenneth L.
Published: November 2008

Abstract: Extracorporeal membrane oxygenation (ECMO) can support neonates with severe respiratory failure. Currently, the most common application of ECMO requires venoarterial access. Venovenous (VV) ECMO is desirable to avoid common carotid artery ligation. However, the best technique of venous access for VV ECMO is not established. Using a single cannula with a double‐lumen (DLC) in the right atrium for simultaneous drainage and infusion of blood, VV ECMO provided total respiratory support for six apneic puppies for 3 h each. Mean systemic arterial oxygenation was lower with DLC VV (50 torr) compared to VA ECMO (247 torr), but a physiologic pH (mean 7.34) was maintained on DLC VV bypass. Higher mean bypass flow was required on DLC VV (124 ml/kg/min) compared to VA flow (101 ml/kg/min) because of recirculation of oxygenated blood. The position of the DLC in the right atrium needed to be closely monitored. Hemorrhage was noted in the myocardium after use of DLC VV ECMO.
The Need for Teaching Artificial Organ Technology in Medicine: Learning from the Kidney
Authors: Bonomini Vittorio
Published: November 2008

Abstract: In organ replacement therapy, there are lessons to be learned from the biological, clinical, social, and educational implications of renal replacement therapy, the kidney being first among other organs in the quality and quantity of therapy. In the light of the teaching potential of these lessons, no pre‐or postgraduate educational reforms can afford to ignore the fruit of 20 years, of renal replacement therapy.
The Treatment of Cancer with Activated Cytotoxic Leukocyte Subsets
Authors: Stevenson Henry C. , Stevenson George W. , Lacerna Leocadio V.
Published: November 2008

Abstract: Cancer biotherapy focuses on stimulating natural defense mechanisms designed to control or eradicate cancer. Many distinct cancer biotherapy strategies have been formulated over the past two decades; one of the most promising involves the removal of cytotoxic leukocyte subsets from cancer patients, augmenting the cytotoxic function of these cells ex vivo and re‐administering these activated cells with additional function‐enhancing biologicals. This approach is termed adoptive cellular immunotherapy and is best represented at present by the activated killer monocyte and the lymphokinc activated killer cell therapies. The activation of cytotoxic monocytes with gamma interferon and the activation of cytotoxic lymphocytes with interleukin‐2 are prototypic examples of adoptive immunotherapy research activity which is likely to expand in the near future.
Exchange Blood Transfusion for Acute Hepatic Failure: Its Limited Availability Depending on the Type of Injury in Rats
Authors: Fujiwara Kenji , Oka Yuji , Ogata Itsuro , Ohta Yasuhiko , Sato Yuzuru , Masaki Naohiko , Takatsuki Katsuyoshi , Oka Hiroshi
Published: November 2008

Abstract:The efficacy of exchange blood transfusion for acute hepatic failure was evaluated using rats. Rats receiving a dose of carbon tetrachloride died later than 24 h after dosing. When their blood was replaced with blood from normal rats at 24 h, survival time was prolonged, and hepatic protein synthesis was enhanced at 36 h with improved prothrombin time (PT). Those rats surviving 120 h showed better histological grade of recovery from injury after treatment. In contrast, dimethylnitrosamine (DMN)‐mtoxicated rats showed no such improvement in survival time or PT. In rats given a nonfatal dose of carbon tetrachloride, serum glutamic‐pyruvic transaminase values were five times higher than those in rats given DMN despite similar maximal PT. The benefit of exchange transfusion for acute hepatic failure may differ depending on the mechanism of development in rats. Enhanced hepatic protein synthesis may contribute to its effect.
Prevalence and Causes of Long‐Lasting Hepatic Dysfunction after Heart Transplantation: A Series of 80 Patients
Authors: Cadranel J. F. , Grippon P. , Mattei M. F. , Lunel F. , Pauwels A. , Rossant P. , Karkouche B. , Cabrol A. , Chomette G. , Cabrol C. , Opolon P.
Published: November 2008

Abstract:The long‐term follow‐up of 80 heart transplant patients (70 men, 10 women) from January 1982 to July 1985 who had received cyclosporine (CsA) showed a high incidence of mild to severe liver dysfunction. Fifty patients (62.5%) had long‐lasting postoperative biological disturbances (alanine amino transferase >2N and/or alkaline phosphatase >1.5N for 3 months or more). Most patients were asymptomatic; eight were icteric, and one had arthralgia. The most common biological feature consisted of isolated elevation of ALAT (27 cases). Assessment of causes led to a definite etiology in 42 patients: 7 cardiac failure, 13 HBsAg‐positive liver disease (26%) (chronic persistent hepatitis 8, chronic active hepatitis 2, subacute necrosis 2). Fourteen patients (28%) sustained non‐A, non‐B (NANB) hepatitis (chronic persistent hepatitis 5, chronic active hepatitis 1, cirrhosis 1), and 7 (14%) sustained a drug‐related hepatitis. Liver biopsy and complete virus screening was contributive to the diagnosis in nearly all patients. Additionally, prolonged impairment of liver function tests occurred in 62% of heart transplant recipients, mostly during the first 6 postoperative months. Hepatitis B virus (HBV) and NANB hepatitis accounted for 26% and 28% of the cases of liver dysfunction, respectively; drug‐induced hepatitis may have been involved in 14% of the cases. Complete hepatitis virus screening should be performed before heart transplant and in any case of abnormal liver function posttransplantation. HBV vaccination prior to heart transplant is recommended in HBsAg‐and HBcAb‐negative candidates for heart replacement. Long‐term follow‐up of these patients is mandatory to assess the severity of these liver dysfunctions.
An Artificial Lymph Gland: A New Approach to Cancer Therapy
Authors: Pineda A. A. , Sniecinski I. J. , Stevenson H. C.
Published: November 2008

Abstract: We are witnessing the initial stages of an era of extracorporeal blood cell manipulation aimed at amplifying, modifying, modulating, and regulating immune function. In some respects, this manipulation reproduces lymph organ functions. The basic technology is blood cell separation by continuous flow centrifugation resulting in isolation of mononuclear cells. These cells are activated in‐vivo and ex‐vivo with biological response modifiers. These modifiers appear to have applicability in the adoptive immunotherapy of cancer as shown in preliminary data obtained with lymphokine‐activated killer (LAK) cells used in the treatment of advanced cancer in humans. The potential utilization of lymphokines as activators of tumoricidal activity by immunologic effector cells harvested from the cancer patient by cytapheresis is the subject of active research.
The Mitroflow Pericardial Valve
Authors: Loisance D. , Hillion M. L. , Cachera J. P.
Published: November 2008

Abstract: One hundred eighty‐eight Mitroflow pericardial valves, implanted on 166 patients from March 1983 to December 1986, have been followed for a total of 4316 patients x months. Mortality rate in the first three postoperative months is approximately 10% related to noncardiac complications. One hundred forty‐nine patients are living at the start of the follow up period. During that period, one valve was explanted after 22 months for a cusp tear. The rate of thrombo embolic episode is minimal, six cases, as 47% are free of any anticoagulant therapy. One patient, operated upon for active SBE, required additional surgery 2 months later for a prosthetic infection. The present results suggest that early primary failure of Mitroflow valve is quite unfrequent.
Animal Evaluation of a New Pericardial Bioprosthetic Heart Valve
Authors: Spyt T. J. , Fisher J. , Reid J. , Anderson J. D. , Wheatley D. J.
Published: November 2008

Abstract: Implantation in animals is an essential step in the evaluation of any new prosthetic heart valve before commencing clinical trials. A new three‐leaflet pericardial bioprosthesis developed in Glasgow has been implanted in the mitral position in ten sheep and eight dogs. Eleven animals were electively killed after 3 months of observation and explanted valves were in good condition. Hydrodynamic tests of the explanted valves showed small changes in function compared to tests prior to implantation. This was mainly due to host tissue ingrowth over the edge of the leaflets. Histological studies confirmed good preservation of the pericardial tissue in explanted valves.
Microencapsulated Hepatocytes for Bioartificial Liver Support
Authors: Cai Zhuhui , Shi Zhiqing , Geraldine M. , O'Shea  , Sun Anthony M.
Published: November 2008

Abstract: Free hepatocytes, harvested from normal rat livers by portal vein collagenase perfusion, were encapsulated within alginate‐polylysine membranes and served as a liver support system. The encapsulated hepatocytes remained viable and were able to synthesize protein for up to 3 weeks in culture. Allografts of encapsulated hepatocytes replaced the function of a damaged liver and reduced the mortality rate among rats with galactosamine‐induced fulminant hepatic failure.
Hydrodynamic Investigation of Mechanical Bileaflet Valves
Authors: Heiliger Raymund , Lambertz Heinz , Geks Josef , Mittermayer Christian
Published: November 2008

Abstract: For hydrodynamic comparison, 11 mechanical bileaflet valves have been perfused in a mock circulation system under pulsatile flow conditions. Six St. Jude Medical valves with different sizes from No. 21 to No. 31 and five Duromedics prostheses with corresponding sizes from No. 21 to No. 29 have been investigated. Flow, pressure, and orifice area were measured, while cardiac output was varied between 2 and 6 L/min. Insufficiency (I), maximal orifice area (Amax), mean orifice area (A), discharge coefficient (CD), performance index (PI), and efficiency index (EI) were determined. The St. Jude Medical valves show higher values of orifice area when compared with the Duromedics valves. For smaller valve sizes up to No. 25, the values of the orifice area are similar. The Duromedics valves show much lower values of insufficiency; thus, for small valve sizes, the Duromedics prosthesis seems to be superior. For larger valve sizes (No. 27, No. 29, and No. 31), a decision has to be made whether higher insufficiency and higher orifice area of the St. Jude Medical valve or lower insufficiency with lower orifice area is more acceptable.
Cefoperazone in the Treatment of Peritonitis in Continuous Ambulatory Peritoneal Dialysis Patients
Authors: Leehey David J. , Reid Ralston , Chan Alex Y. , Ing Todd S.
Published: November 2008

Abstract: Cefoperazone is a third‐generation cephalosporin that is active against a broad spectrum of gram‐positive and gram‐negative bacteria. We added this antibiotic to peritoneal dialysis solution at a concentration of 62.5 mg/L to treat peritonitis in six continuous ambulatory peritoneal dialysis (CAPD) patients. Serum drug concentrations were obtained at 0, 0.5, 1, 2, 4, and 24 h after instituting antibiotic therapy. Rapid uptake by blood of the antibiotic across the peritoneal membrane occurred when the latter was inflamed. Adequate bactericidal serum levels for many bacteria were obtained in less than 4 h. Cefoperazone effectively eradicated peritonitis in all patients.
Protein A Immunoadsorption Therapy in HIV‐Related Immune Thrombocytopenia: A Preliminary Report
Authors: Bertram Juergen H. , Snyder Harry W. , Gill Parkash S. , Shulman Ira , Henry David H. , Jenkins Donella , Kiprov Dobri D.
Published: November 2008

Abstract: Nine homosexual patients with immune thrombocytopenia were treated with autologous plasma that had been perfused over silica‐immobilized Staphylococcus aureus protein A (SpA). Pretreatment platelet counts ranged from 10,000 to 98,000 cells/mm3(mean: 54,000 cells/mm3). Six patients responded to therapy. Platelets increased by a mean of 95,000 cells/mm3 (p<0.007) and reached normal levels (>150,000 cells/mm3) in four patients. Increased platelet counts are presently sustained in these four individuals after 5 months of follow‐up. Increases in platelet counts significantly correlated with decreases in platelet‐associated IgG (PAIgG), platelet‐directed IgG (PDIgG), and immune complexes (CIC). PAIgG and PDIgG declined by a mean of 67% (p<0.003) and 58% (p<0.007), respectively. CIC decreased by a mean of 37% (p=0.02). Complement was concomitantly activated in all four examined patients. C3a and C5a increased 23‐fold and 2.6‐fold, respectively, while total hemolytic complement decreased by 50%. Activated complement components and removal of CIC and IgG thus may contribute to the platelet‐enhancing activity of SpA immunoadsorption therapy.
Complement Activation Produced by Biomaterials
Authors: Chenoweth Dennis E.
Published: November 2008

Abstract: : The complement‐activating potential of biomaterials may be defined by appropriate application of C3a and C5a anaphylatoxin radioimmunoassays. Studies performed with hemodialysis membranes demonstrate that blood contact with these model biomaterials results in complement activation that may be ascribed to specific properties of the material surface. Further delineation of these chemical and physical properties may permit design of biocompatible materials.
Renal Epithelial‐Cell‐Controlled Solute Transport Across Permeable Membranes as the Foundation for a Bioartificial Kidney
Authors: Ip Tze Kin , Aebischer Patrick
Published: November 2008

Abstract: Despite the success of current blood purification techniques in allowing the survival of individuals with acute and chronic renal failure, the quality of life of people affected by end‐stage renal disease remains unsatisfactory. Part of the reason is due to the nonphysiologic manner in which current blood purification techniques achieve homeostasis. Attempts to improve mechanical substitution of renal function by coupling the transport capability of living cells with conventional hemofiltration devices constitute the first step toward the development of an implantable bioartificial kidney.
Comparison of Various Treatment Modes in Terms of ß2‐Microglobulin Removal: Hemodialysis, Hemofiltration, and Push/Pull HDF
Authors: Shinzato Takahiro , Kobayakawa Hiroyuki , Maeda Kenji
Published: November 2008

Abstract: The ß2‐microglobulin clearance increased as the convective transport was added during hemodialysis to perform hemodiafiltration (HDF), suggesting that a convective transport type artificial kidney is more effective for ß2‐microglobulin removal. Actually, the decrease in the plasma ß2‐microglobulin level per treatment was more pronounced in hemofiltration and push/pull HDF than in hemodialysis. In the present study, no significant fluctuation in the pretreatment level of ß2‐microglobulin was shown by serial treatment by hemodialysis, whereas an obvious decreasing trend of it was indicated in serial treatment of either push/pull HDF or hemofiltration. Moreover, our study indicated that the ratio of posttreat‐ment ß2‐microglobulin level in relation to its pretreatment level increases as the treatment by hemofiltration or push/ pull HDF is repeated.
In Vitro Comparison of Velocity Profiles and Turbulent Shear Distal to Polyurethane Trileaflet and Pericardial Prosthetic Valves
Authors: Chandran K. B. , Fatemi Reza , Schoephoerster Richard , Wurzel D. , Hansen G. , Pantalos G. , Yu L. S. , Kolff W. J.
Published: November 2008

Abstract: A comparative study of flow dynamics past bi‐omer trileaflet valves and a pericardial bioprosthetic valve under steady and physiological pulsatile flow conditions in vitro is reported in this paper. The velocity profiles and the turbulent shear stresses distal to the valves were measured using laser Doppler anemometry. The authors' results showed that the velocity profiles distal to the trileaflet valves were similar to that measured distal to the pericardial valve. Higher magnitudes of absolute turbulent shear stresses were measured distal to the synthetic valves in comparison to the pericardial valves. However, when the stresses were nondimension‐alized with respect to the orifice diameter at the inlet aspect, the stresses were comparable for all of the three valves. With design modifications to increase the orifice diameter at the inlet aspect of the polyurethane valves, the turbulent stresses distal to the valves can be minimized. Such in vitro studies on the flow dynamics past the polyurethane valves can provide information towards design changes to improve the performance characteristics of these valves. Polyurethane valves with flow characteristics comparable to the pericardial valves can be manufactured relatively inexpensively compared to mechanical or tissue valve prosthesis. Hence, the synthetic valves may be a viable alternative for short‐term use in total artificial heart devices as a bridge to transplant.
Effects of Pyridoxalated Hemoglobin Polyoxyethylene Conjugate and Stroma‐Free Hemoglobin on Cardiac Function in Isolated Rat Heart
Authors: Yamakawa Takashi , Miyauchi Yoshimasa , Nishi Katsuhide
Published: November 2008

Abstract:Effects of a newly introduced modified hemoglobin, pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), and stroma‐free hemoglobin (SFH) on cardiac rhythm and contractility were examined in isolated rat hearts. Hearts were perfused with HEPES‐buffered Krebs solution containing 6% PHP, 6% SFH, or 6% hydroxy ethylstarch (HES). Arrhythmia was not observed in PHP‐perfused hearts, but marked sinus bradycardia occurred in SFH‐perfused hearts. Ventricular contractility assessed by left ventricular pressure and pressure‐volume relationship in both PHP and SFH‐perfused hearts were well maintained during perfusion. There was no significant difference to the coronary flow resistance between hearts perfused with PHP and HES solutions, indicating that PHP has little vasoactive effect. The flow resistance in SFH‐perfused hearts decreased significantly when compared with other groups. Results demonstrate that PHP solution can preserve cardiac function and have no toxic effects in isolated rat hearts.
Noise Level and Perception of the Closing Click After Heart Valve Replacement with St. Jude Medical and Björk Shiley Monostrut Prostheses
Authors: Moritz Anton , Kobinia Georg , Steinseifer Ulrich , Wolters Heinrich , Reul Helmut , Neuwirth‐Riedl Kurt , Grünbacher Günter , Wolner Ernst
Published: November 2008

Abstract: The metallic click generated by the closure of mechanical heart valve prostheses may severely bother patients, but generated sound energy and the extent of complaints after implantation are not known. In 62 patients, after valve Replacement with St. Jude Medical (SJM) (n = 35) and Björk Shiley Monostrut (BSM) (n = 27) prostheses, sound energy was recorded with a calibrated noise level analyzer at 5, 10, and 100 cm distance from patients and correlated with their complaints. At a distance of 100 cm, the BSM valves produced a significantly higher sound pressure level, 30.5 ± 5 db(A), compared to the SJM valves, 24.1 ±4 db(A) (p = 0.0001). There was no significant difference at shorter distances. After splitting into frequency bands the highest sound pressure levels were observed in the high frequency ranges (8 to 16 kHz) representing the metallic click. BSM valves produced higher sound levels in all frequency ranges at 1 m distance. Seventy‐three percent of all patients were aware of the noise generated by the valve; 20% had disturbed sleep; and 26% preferred a less noisy valve type. Twelve of 27 patients with BSM valves wanted less noisy valves, whereas only 4 of 35 patients with SJM valves wished to have a less noisy valve type (Chi‐square p = 0.003). In patients who could hear their valve measured, sound level was higher than in patients who could not. In 9 of 27 patients with BSM (33%), versus 3 of 35 with SJM prostheses (9%), the clicking caused sleep disturbances. In 85% of BSM, versus 63% SJM, patients could hear their valve (p = 0.05). Since higher sound pressure levels generated by the closing click resulted in an increased rate of complaints, noise level should be regarded as a criterion when a mechanical heart valve prosthesis is selected.
Large‐Scale Production and Cultivation of Hepatocytes on Biosilon Microcarriers
Authors: Shnyra Alexander , Bocharov Alexander , Bochkova Natalia , Spirov Valentin
Published: November 2008

Abstract: A method for large‐scale production of hepatocytes on microcarriers have been developed for the purpose of bioartificial liver support system. Hepatocytes obtained by collagenase treatment of rat liver were efficiently attached and spread on a microcarrier surface in the presence of O2‐saturated perfluorodecalin. In order to compare the metabolic activities of hepatocytes under long‐term cultivation on microcarriers with those of cells under conventional monolayer culture, some liver‐specific functions were investigated. Microcarrier‐at‐tached hepatocytes cultured in the absence of serum for 8 days synthesized and secreted albumin and fibronectin.

Moreover, hepatocytes on microcarriers retained the ability to conjugate bilirubin for 4–5 days. With respect to these specific metabolic properties, microcarrier‐attached hepatocytes were comparable to those from routine dish culture. These results suggest that this method developed for large‐scale production of hepatocytes on microcarriers will allow one to obtain metabolically active cells suitable for extracorporeal liver support systems.
Net Ultrafiltration May Not Eliminate Backfiltration During Hemodialysis with Highly Permeable Membranes
Authors: Leypoldt John K. , Schmidt Barbel , Gurland Hans J.
Published: November 2008

Abstract: Backfiltration of dialysis solution can occur during hemodialysis with highly permeable membranes. A method has recently been developed for determining backfiltration rates in vitro at low dialysate flow rates by measuring changes in the local dialysate concentration of a marker macromolecule via sampling ports added to the hemodialyzer housing. In the present study, the influence of net ultrafiltration on backfiltration rates was determined for five commercial dialyzers containing membranes with different water permeabilities. In vitro experiments were performed (n = 3) using freshly donated whole blood at blood flow rates of 200 and 340 ml/min and at a dialysate flow rate of 100 ml/min. At zero net ultrafiltration, backfiltration rates increased with increasing membrane water permeability and ranged from 0.9 to 6.9 ml/min. At a net ultrafiltration rate of 10 ml/min, backfiltration was eliminated for dialyzers containing membranes with water permeabilities of < 30 ml/h/mm Hg but remained significant for dialyzers with higher membrane water permeabilities. Therefore, despite a significant net ultrafiltration rate, backfiltration may still occur during hemodialysis with highly permeable membranes.
Percutaneous Insertion of a Jacketed Stent to Close the Entry of Dissecting Aortic Aneurysms of DeBakey Types I and II
Authors: Karube Norihisa , Noishiki Yasuharu , Yamamoto Kenji , Kondo Jiro , Matsumoto Akihiko
Published: November 2008

Abstract: As a treatment for dissecting aortic aneurysms of DeBakey Types I and II, a percutaneous insertion method using a new jacketed stent was developed. The efficacy of the method was evaluated in an animal study. We developed a special stent prepared by modifying the original Gianturco self‐expandable metallic stent and a fabric patch. A model of a dissecting aortic aneurysm of DeBakey Type I was created in dogs. The device was inserted into the ascending aorta from the left carotid artery through a sheath‐introducer system. The aortogram showed the bloodstream through the false lumen before the insertion, but no bloodstream after the stent insertion. The autopsy showed that the entry, the reentry, and the false lumen were completely filled with fresh thrombus. By using this stent, we successfully achieved an interventional treatment for dissecting aortic aneurysms of DeBakey Types I and II.
Unusual Inflammatory Responses around a Collagen‐Impregnated Vascular Prosthesis
Authors: Yamamoto Kenji , Noishiki Yasuharu , Mo Makoto , Kondo Jiro , Matsumoto Akihiko
Published: November 2008

Abstract: A collagen‐impregnated graft, called Hemashield, has been used clinically; however, some complications such as pyrexia, fluid accumulation, and unusual scar formation around the graft have been reported. To understand the cause of these problems, the graft was examined both in vivo and in vitro. Endotoxin and (1–3)β‐d‐glucan were detected in the extract from Hemashield by special quantative methods called Toxicolor and Endospecy. In an animal study, the grafts were implanted in the thoracic descending aorta of 9 dogs and were designed to explant at 2 weeks. Macroscopic evaluation of the explants showed that the graft had no infection, but fluid accumulation was found in the pleural cavity and around the graft‐like seroma. Microscopical observations revealed that neither fibroblasts nor capillary blood vessels had infiltrated in the adventitial side of the graft, but numerous plasma cells, lymphocytes, and macrophages were noticed. The impregnated collagen was partially absorbed. These results indicate that the graft had some contaminants which contained a certain amount of endotoxin and (1–3)β‐d‐glucan, resulting in noninfective inflammatory responses around the graft.
Is the Biological Artificial Liver Clinically Applicable? A Historic Review of Biological Artificial Liver Support Systems
Authors: Kasai Shin‐ichi , Sawa Masayuki , Mito Michio
Published: November 2008

Abstract: Hemoperfusion, hemodiafiltration, plasma exchange, and extracorporeal liver perfusion have already been adopted to treat patients with acute and chronic hepatic failure. However, the survival rate of patients with acute hepatic failure remains at approximately 30% and has not improved as expected. Current advances in biotechnology have opened the way for the development of a biological artificial liver, which is called the hybrid artificial liver because it consists of both biological and artificial materials. Isolated hepatocytes have been investigated for use in various types of hybrid artificial liver. In addition, the role of biomatrices, microcarriers, and the microencapsulation technique has been studied with respect to long‐term maintenance of hepatocellular function and development of high‐density culture systems for hepatocytes. Before clinical application of hybrid artificial liver support systems becomes possible, many problems have to be resolved, including large‐scale preparation and long‐term preservation of biomaterials, high‐density and stable immobilization of biomaterials on artificial materials, control of immunological hazards, biocompatibility, safe transportation and sterilization of biomaterials, and the high cost. We review the history of biological artificial livers and discuss their future role.
Development of a Bioartificial Liver Using Isolated Hepatocytes
Authors: Dixit Vivek
Published: November 2008

Abstract: Severe liver disease is very often life‐threatening and dramatically diminishes quality of life. Liver support systems based on detoxification alone have been proved ineffective because they cannot correct biochemical disorders. An effective artificial liver support system should be capable of carrying out the liver's essential processes, such as synthetic and metabolic functions, detoxification, and excretion. It should be capable of sustaining patients with fulminant hepatic failure, preparing patients for liver transplantation when a donor liver is not readily available (i.e., bridge to transplantation), and improving the survival and quality of life for patients for whom transplantation is not a therapeutic option. Recent advances in cell biology, tissue culture techniques, and biotechnology have led the way for the potential use of isolated hepatocytes in treating an array of liver disorders. Isolated hepatocytes may be transplanted to replace liver‐specific deficiencies or as an important element of an auxiliary hybrid, bioartificial extracorporeal liver support device, which are important therapeutic applications for treating severe liver disease. Recently, several hepatocyte‐based liver support systems have been proposed. Although there is no current consensus on its eventual design configuration, the hollow fiber hepatocyte bioreactor shows the greatest promise. Furthermore, application of tissue engineering technology, based on cellsurface interaction studies proposed by our group and others, has enhanced interest in the development of highly efficient hybrid, bioartificial, liver support devices.