bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudointima in Expanded Polytetrafluoroethylene Graft Implanted in the Inferior Vena Cava of Normal and Defibrinogenated Dogs
Authors: Ishimaru Shin , William‐Olsson Eva Berglin , Hansson Hans‐Arne , Teefer‐Nilsson Ann‐Catrine , William‐Olsson Goran
Published: November 2008

The pseudointimal formation in an expanded polytetrafluoroethylene graft implanted in the canine inferior vena cava was studied by light and transmission electron microscopy. Five of 6 grafts in the control group and all the 10 grafts in the batroxobin‐defibrinogenated group were patent, and provided for the investigation.

The thickness of the mural thrombus formed within 3 days was significantly decreased in the severely defibrinogenated dogs, in which the fibrinogen concentration was below 0.40 gm/L, as compared to the controls and the moderately defibrinogenated dogs, in which the fibrinogen concentration was at highest 0.72‐0.87 gm/L.

In spite of reducing the fibrinogen concentration to unmeas‐urable levels after 3 days, there was no obvious difference in the process of pseudointimal formation between the moderately defibrinogenated dogs and the controls. In the severely defibrinogenated dogs, loose and spongoid mural thrombus required a longer time to be reorganized.
Continuous Cyclic Peritoneal Dialysis: A Preliminary Report
Authors: Diaz‐Buxo Jose A. , Farmer Charles D. , Walker Phillip J. , Chandler Joe T. , Holt Kenneth L.
Published: November 2008

Continuous cyclic peritoneal dialysis (CCPD) was designed to reduce the high incidence of peritonitis and eliminate the multiple interruptions created by dialysate exchanges during the day needed for CAPD, while maintaining the quality of dialysis. Three nocturnal cycles with 2 liters of dialysate lasting 3 hours each are provided by an automated cycler while the patient sleeps. Two liters are left in the abdomen in the morning. Only one daily connection and one disconnection are required between the peritoneal catheter and the cycler line. Our 84 patient months experience with 14 patients reveals a low incidence of peritonitis (1 per 42 patient months), satisfactory ultrafiltration rates and clearances that compare favorably with those of CAPD (Curea 67, Ccreatinine 58, and CB12 45 L/wk). Blood pressure control has been excellent while most patients enjoy liberal diets.

This preliminary study suggests that CCPD may indeed reduce the rate of peritonitis, provide excellent clearance and ultrafiltration, allow more free time to the patient and maintain a steady physiological state.
Current Status of Therapeutic Apheresis in Rheumatoid Arthritis
Authors: Wallace Daniel J. , Goldfinger Dennis , Klinenberg James R.
Published: November 2008

Evidence developed over the years has suggested that lymphocyte depletion and removal of plasma factors can ameliorate rheumatoid arthritis. In our studies of 40 patients, a subset of patients that respond best to 20 therapeutic lymphaplasmapheresis over 11 weeks has emerged. These are functional Class III patients with seropositive, erosive progressive disease who have little deformity. They must be on long‐acting agents or cytotoxic drugs during pheresis to prevent antibody rebound. Other studies have since confirmed our work. The major side effects of pheresis are elucidated. Technologic developments will enable selective pheresis procedures to be in widespread use within a few years.
150‐Day Survival of a Calf with a Polymethylmethacrylate Total Artificial Heart: TNS‐BRNO‐II
Authors: Vašků Jaromír , černý Jan , Hanzelka Pavel , Vašků Jan , Urbánek Erich , Dostál Miloslav , Urbánek Petr , Guba Peter , Pavlíček Viktor , Krček Lubomír , šSládek Tomá , Hartmannová Brigita , Filkuka Jaroslav , Janečková Helena , šotolová Olga , šotáková Eva , Doležel Svatopluk , Krčma Vladimír , Cídl Karel , Bednarřík Bohumil
Published: November 2008

A 150‐day experiment in a calf with an implanted total artificial heart, TNS‐BRNO‐II, is described. The Czechoslovak TAH‐BRNO‐II device is a hybrid; the outer housing is made of polymethylmethacrylate, the moving parts of segmented polyurethane. The blood flow through the device after the surgery gradually increased from 7 L/min to 12 L/min by the end of the experiment. Atrial pressures were automatically maintained at the same level, about one kPa on both sides. The left systolic time was automatically derived from the pump emptying phase; the right systolic time was maintained between 40% and 50%. After the surgery, normal values of blood gases, stabilization of respiratory activity, and normalization of gastrointestinal functions were reached very soon. Anticoagulant therapy was performed during the whole experiment, with several periods of increased bleeding tendency. The clinical state of the calf was essentially physiological until the 94th day of the experiment, when acute bronchopneumonia, with a high fever, over 41°C, initiated a series of complications (pseudomembranous enterocolitis, followed by sepsis lenta). The fatal complication was sudden impairment of the coagulation mechanisms on the 149th to 150th day of the experiment. This was the basic reason for the subsequent death of the animal, caused by acute cerebral anemic anoxia, which could not be prevented by immediate therapeutic procedures. In spite of these complications, the clinical state of this calf was relatively good until the end of the experiment. Autopsy revealed minimal thromboembolization at the valves. The outer surface of the diaphragm was covered with pseudoneointimal deposits and the inlet orifices were free of pannus or other connective tissue crescents. Macroscopic signs of infection were not seen, but bacteriological cultivation from internal organs confirmed Klebsiella infection. The state of the device at the time of autopsy, with simultaneous undisturbed function of the control and driving unit, showed the possibility of still longer survival.
Effect of Incubation Temperature on Human Red Cell Survival
Authors: Lee Minako Y. , Uvelli David A. , Finch Clement A. , Babb Albert L.
Published: November 2008

The effect of in vitro exposure of normal human erythrocytes to temperatures between 41°C and 43°C for two hours was determined. In vivo survival was measured employing 51Cr and 14C‐cyanate as red cell tags. No significant difference was observed between cells exposed to these temperatures and erythrocytes incubated at 37°C. The results of this study are of value in various types of extracorporeal blood treatment where an elevated temperature is desired.
Acetate Suppresses Growth Hormone Secretion in Uremic Patients: Hemodialysis and Acetate Infusion Experiments
Authors: Schmitz O. , Hansen Aa. Prange , Hansen H. E. , Ørskov H. , Alberti K. G. M. M.
Published: November 2008

Growth hormone secretion in uremic patients is completely suppressed immediately after initiation of and during hemodialysis using acetate dialysate. The present study demonstrates that growth hormone secretion stimulated by arginine is also inhibited by hemodialysis. Acetate infusion experiments proved that the high blood acetate level obtained during dialysis is at least partly responsible for this growth hormone suppression by unknown mechanisms.
Selection of Filters and Evaluation In Vitro of the Selective Dual Filtration Artificial Kidney, SEDUFARK
Authors: Svartaas Thor M. , Smeby Leif C. , Jørstad Størker , Naess Tove B. , Widerøe Tor‐Erik , Holtz Manfred
Published: November 2008

Transport properties of different artificial kidney membranes have been studied employing substances with molecular weights ranging from 60 daltons (urea) to 62,000 daltons (dextran). The results from these studies were used to select filters for the SElective DUal Filtration ARtificial Kidney, SEDUFARK.

Selection criteria for filters to be used in long‐term clinical trials with SEDUFARK were based on biological tests showing toxicity of large molecular weight substances in uremic blood plasma and clinical advantages of returning middle molecular weight substances to the patient. The filters selected were used for evaluation in vitro of the complete SEDUFARK system. The results confirmed a theoretical analysis of this system, demonstrating that selective removal of substances within given molecular weight ranges from uremic blood plasma is feasible with a combination of commercial filters. The efficiency of the system, however, is limited due to the “cut‐off‘ characteristics and hydraulic permeabilities of membrane types currently available.
The Effect of Repeated Hemoperfusion Over Charcoal in the Conscious Rat on Liver Pathophysiology
Authors: Ryan Calvin J. , Courtney James M. , McLay Arthur L.C. , Wood Christopher B. , Blumgart Leslie H.
Published: November 2008

An investigation has been made into the effects of repeated charcoal hemoperfusion in the rat on liver pathophysiology. Animals underwent hemoperfusion over Norit RBX1 charcoal using a technique which allowed perfusion in the unrestrained and conscious state, thus minimizing any possible effects from stress and eliminating the necessity of repeated anesthesia. Controls consisted of animals subjected to perfusion through empty columns and animals cannulated only. Liver weight, function, and histology were recorded at various times following hemoperfusion and control procedures. The results show that repeated charcoal hemoperfusion is well tolerated in the rat and can be performed safely with no deleterious effects on liver tissue.
Hemoperfusion and DNA Synthesis in the Rat Liver Part I: The Effect of Hemoperfusion on the Rate of DNA Synthesis
Authors: Ryan Calvin J. , Courtney James M. , Wood Christopher B. , Blumgart Leslie H.
Published: November 2008

An investigation has been made into whether charcoal hemoperfusion stimulates a hyperplastic response in the liver of the normal rat. Animals underwent hemoperfusion over Norit RBX1 (Strathclyde, Glasgow, U. K.) charcoal granules using a technique which allowed perfusion in the unrestrained and conscious state. Controls consisted of animals subjected to perfusion through empty columns and animals cannulated only. Body weight, liver weight, function, and DNA synthesis were recorded at various times after completion of perfusion and control procedures. The results indicated that charcoal hemoperfusion did not stimulate a hyperplastic response in the liver of the normal rat following perfusion, and did not produce marked changes in body weight, liver weight, and function.
Soviet‐American Collaboration on the Development of an Artificial Heart and Mechanical Circulatory Assistance
Authors: Shumakov Valeriy I.
Published: November 2008

Summary: Soviet‐American collaboration has resulted in more in‐depth studies on the artificial heart and assisted circulation during the period of 1974–1980. The American investigators received assemblies for the Kedr (with atria and volume capacity gauges) and the Poisk and Module (without atria) artificial heart, and the pneumatic drive and automatic control system for the three artificial heart models. The Soviet investigators received from the Baylor College of Medicine the artificial heart assembly including the Vitamekr̀ pneumatic drive for the artificial heart, the biomaterials Avcothane and biomer for preparation of the artificial heart parts, and a vacuum molder for fabricating the housings of the artificial ventricles. The artificial hearts were tested on hydrodynamic benches and in animal experiments (the American artificial hearts were tested in the U.S.S.R., and the Soviet artificial hearts in the U.S.A.). Comparative study on the hydrodynamic bench, conducted according to a jointly developed, standardized method, showed that the Module artificial heart had the best flow characteristics. Valuable information was obtained concerning the Vitamek pneumatic drive and the automatic control systems, as well as the balloon pumps and drives manufactured in the U.S.S.R. and the U.S.A.
In Vitro Assessment of the Hemocompatible Properties of Polymers
Authors: Sevastianov Viktor I. , Belomestnaia Zinaida M. , Zimin Nikolai K.
Published: November 2008

Summary: Based on the available data in the literature and personal results, a system of in vitro tests, consisting of two levels of selection, was proposed for assessment of hemocompatible properties of polymers. The first level consists of rapid methods for preliminary assessment (clotting time, hemolytic activity of the sample, and number of adhesive platelets). The second level involves methods for final selection and consists of measurement of the kinetics of the initial stages of adsorption of albumin, the degree of activation of the complement system, the intensity of radical oxidation of the lipid fraction of the blood, and the degree of platelet spreading. Comparative experimental assessment of these methods was conducted with a number of polymers and revealed the confidence limits for the application of each test and suggested quantitative criteria for selection.
Organization of Treatment of Patients with Cardiac Insufficiency of Different Origin
Authors: Balakirev Eduard M. , Tolpekin Vladimir E.
Published: November 2008

Summary: Assisted circulation is now used in the treatment of severe forms of heart failure which complicate the course of many diseases. Application of one method of assisted circulation‐intra‐aortic counterpulsation by a balloon pump in cardiogenic shock‐was successful: prolonged survival (over 1 year) was obtained in 18% of the patients. A further decrease in the mortality rate is dependent on the rational organization of treatment for these patients. This poses two major problems: the organization of treatment of patients in cardiogenic shock and postoperative heart failure in large cardiologic and heart surgery centers, and treatment of heart failure in patients in whom it has occurred secondarily. We developed a method of organizing the treatment of these patients beginning in the prehospital stage and continuing in a specialized hospital. In addition to methods of assisted circulation, various intensive care methods and hemosorption (in poisoning by liver toxins), hemodialysis (in anuria), etc., are used. Although this type of organization complicates therapy, the results are significantly improved.
The Thin‐Film Adsorber Hemoperfusion Device: Detailed Mass Transfer and Flow Characteristics
Authors: Cooney David O. , Kane Robert P.
Published: November 2008

Abstract: Further testing and evaluation of the thin‐film adsorber (TFA) type of hemoperfusion device is Reported here to complement an earlier paper describing the development of these devices and clearance test's performed with them. The present paper describes the results of pressure drop tests, flow uniformity tests, and detailed studies of the mass transfer characteristics of the components of the TFA units. The TFA units consist of powdered activated charcoal embedded in thin films of cellulose nitrate. These films are sprinkled with small particles of granular charcoal and then wound into spools, which are then placed in a plastic housing. The use of powdered charcoal exploits the enormous rate‐of‐uptake advantage of powdered charcoal over the granular sorbents used in other hemoperfusion devices. The present tests showed that the pressure drops in the TFA devices are intrinsically low, but that their priming volumes are only marginally acceptable. Significant flow nonunifor‐mities also exist. Despite this, the overall mass transfer resistance values for the TFA devices are lower than those for available commercial hemoperfusion units. Measurements of diffusion coefficients in the carbon and in the carbonloaded polymer film showed that in the carbon‐loaded film, the slowest diffusion step involves the carbon particles themselves. Other tests disclosed that the liquid external to the film (i.e., in the flow spaces) offers even greater mass transfer resistance than does the carbon‐loaded film. Further evaluations of the TFA type of device are suggested, particularly concerning its thrombogenic properties.
Characterization of Polyethylene Membrane for Plasma Separation
Authors: Sato Hiroshi , Malchesky Paul S. , Matsubara Shuji , Nosé Yukihiko
Published: November 2008

Abstract: Three types of polyethylene hollow fiber membranes (Mitsubishi, Tokyo) were evaluated for plasma separation: EHF‐Type 1 (lowest porosity and smallest inner diameter), Type 2 (medium porosity and diameter), and Type 3 (highest porosity and largest inner diameter). Characterization of these membranes led to the selection of the Type 3 membrane as the best, based on in vitro studies of filtration and sieving properties. Analysis of the data suggests that pore size and pore number (density) are more optimal for this membrane. Ex vivo studies of the Type 3 membrane showed high sieving (> 0.9) for albumin, total protein, and total cholesterol; each was stable over time. No significant hemolysis was observed.
Respiratory Gas Exchange Through the Hydrophilic Membrane
Authors: Zborowski Maciej
Published: November 2008

Abstract: To assess the efficiency of respiratory gas exchange in vitro through a dialysis membrane mounted inside a flat plate Kiil dialyzer, the model reactions of hydrogen peroxide reduction by a metal ion and of the carbon dioxide precipitation in the form of a carbonate in the dialysate were used. A comparison of the rates of oxygen output obtained for a membrane fixed in the test chamber and those for a membrane inside the dialyzer showed that the performance of the membrane as an oxygen source in the latter arrangement is much poorer than that in the former one. This was attributed to the inadequate dialysate channel geometry of the dialyzer with respect to the catalytic reaction. However, the dialyzer geometry did not impede a quick removal of carbon dioxide. Washout of the catalyst (cobalt oxide) was observed. Hydrogen peroxide leakage to the blood side of the membrane was negligible.
Coronary Artery Anatomy of the Goat
Authors: Lipovetsky German , Fenoglio John J. , Gieger Michael , Srinivasan Manu R. , Dobelle Wm. H.
Published: November 2008

Abstract: The coronary arteries of the goat heart were studied using angiographic techniques and molds of the coronary vessel trees. Blood supplies to the left and right ventricles, interventricular septum, atrioventricular node, and apex of the caprine heart were studied. The goat possesses a left dominant pattern of coronary supply with relatively uniform coronary anatomy and may provide a good large animal model for testing cardiovascular assist devices.
Unipuncture Membrane Plasmapheresis
Authors: Verbanck Johan J. , Vanholder Raymond , Schelstraete Jacques , de Clippele Marc , Wulfrank Denis A. , Deschryver Andre E. , Ringoir Severin M.
Published: November 2008

Abstract: A simple method of plasma exchange is presented that uses a hollow‐fiber plasma filter together with conventional unipuncture dialysis equipment. The procedure was well tolerated for eight biweekly sessions in a patient with metastatic breast cancer.
Prediction of Postdialysis Serum Sodium Concentration and Transcellular Fluid Shift Without Measuring Body Fluid Volumes
Authors: Kimura Genjiro , Van Stone John C. , Bauer John H.
Published: November 2008

Abstract: The postdialysis levels of serum sodium concentration, urea concentration, and osmolality, as well as the magnitude of both transcellular fluid shifts and sodium removal, were predicted based on computer modeling without measuring body fluid volumes. A 4‐h hemodialysis was performed in five patients at a constant ultrafiltration rate of 0.5 L/h using dialysate with normal (141 mEq/L) or high (150 mEq/L) Na+ concentration. The serum sodium concentration, urea concentration, and osmolality, as well as intracellular and extracellular fluid volumes, were determined before and after hemodialysis. The model predictions without measurement of body fluid volumes were in excellent agreement with measured values, suggesting clinical validity. The model may be useful in clinical practice to control the postdialysis levels of sodium and water content by computerized hemodialysis.
A Comparative Study of a Group of Eight Calves, Surviving Longer than 1 Month with the Total Artificial Heart
Authors: Vaŝků Jaromír , Ĉerný Jan , Vaŝků Jan , Urbánek Erich , Dostál Miloslav , Urbánek Petr , Guba Peter , Pavlíĉek Viktor , Sládek Tomáŝ , Smutnŷ Miloŝ , Úlehla Tomáŝ , Hartmannová Brigita , Trbuŝek Vojtêch , JaneĉkovAaA Helena , ŜotolovAaA Olga , Ŝotáková Eva , Wendsche Peter , Doleẑel Svatopluk , Filkuka Jaroslav , Gregor Zdenêk , Bednar̂ík Bohumil , Svoboda Petr
Published: November 2008

Abstract: Over the last 21/2 years, eight calves with implanted total artificial hearts (from experimental group IV) have survived for >1 month. In this group two subgroups were further differentiated, subgroup IVa, including three calves surviving 31, 35, and 75 days, and subgroup IVb, with five calves surviving 104, 142, 150, and 155 days and one calf still surviving >160 days. Mean survival in the fourth group was > 106.5 days. The artificial ventricles used were the TNS‐BRNO‐II made of polymethylmethacrylate (seven calves) and the TNS‐BRNO‐III, made of segmented polyetherurethane (one calf). The controller and driving units were of our own design. The Chirasist‐TN‐3 and TN‐4 worked without trouble over the total duration of the studies in all calves. Autoregulation of suction was used in three of these calves. All calves survived in good physiological condition; however, some common changes were observed in all of them, such as a gradual central venous pressure increase and liver enlargement. Anticoagulation therapy was used in all calves. Causes of death were technical in three cases and biological in four. Body weight gains were normal in the majority of these calves, with slight individual differences observed. Diaphragm mineralization of various degrees was observed in three cases. In one of them it was directly related to the cause of death. These results are very encouraging for further development of the total artifical heart research in our center.
A Perfluorochemical Emulsion as an Oxygen Carrier
Authors: Yokoyama Kazumasa , Suyama Tadakazu , Okamoto Hiroyuki , Watanabe Masahiro , Ohyanagi Harumasa , Saitoh Yoichi
Published: November 2008

Abstract: Fluosol‐DA 20%, a perfluorochemical emulsion consisting of 7 parts perfluorodecalin (FDC) and 3 parts perfluorotripropylamine (FTPA), has been used as an oxygen carrier in clinical studies. The emulsion, however, must be stored frozen because it is not stable for long in a liquid state. To increase the stability of perfluorochemical emulsions, a series of experiments on stability, elimination, and toxicity were conducted on different perfluorochemicals. F‐4‐Methyloctahydroquinoli‐dizine (FMOQ) was selected as the best material. The tissue half‐life of FMOQ in rats was estimated to be 7 days, which is the same as that of FDC, a perfluorochemical in Fluosol‐DA 20%. FMOQ emulsified with a mixture of yolk phospholipid and Pluronic F‐68 was stable at 4d̀C for 6 months. Rats exchange‐transfused to a hematocrit of 4% with this emulsion survived for 13 weeks.

Summary: The results of this study indicate that the molecular size of and presence of heteroatoms in the PFCs affect excretion rate and emulsion stability. The presence of heteroatoms in the structure probably increases the emulsion stability. Based on those findings, several kinds of bicyclic amines were studied to find PFCs that have a high excretion rate and form a stable emulsion.

FMOQ emulsified with a mixture of 2% Pluronic F‐68 and 2% yolk phospholipid is more stable than Fluosol‐DA 20% during thermal stress and over long‐term storage. This emulsion can be sterilized by heating and can be stored at 4d̀C for >6 months without deterioration. The elimination rate of this compound from the organs is about five times higher than that of FTPA and similar to that of FDC. The half‐life in the tissue of rats given 4 g/kg FMOQ was calculated to be ˜7 days. All of the 10 rats exchange‐transfused with FMOQ emulsion at a hematocrit of 4% survived, and the hematocrit and hemoglobin levels normalized rapidly. Three months after the exchange transfusion, no histological changes were found even in the liver and spleen, although a small amount of FMOQ was detected in these organs.

From the results obtained, it is concluded that. FMOQ is the most suitable candidate for a second generation oxygen transporter.
The Compliance Problem: A Major Obstacle in the Development of Implantable Blood Pumps
Authors: Lee Soomyung , Rosenberg Gerson , Donachy James H. , Wisman Craig B. , Pierce William S.
Published: November 2008

Abstract: The compliance problem represents a major obstacle in the development of implantable blood pumps. The motor‐driven pumps are enclosed in an airtight casing with gas in the motor space. The trapped gas in the motor space either increases the load on the motor during systole or impedes blood sac filling. Potential solutions to the compliance problem include the use of a conventional blood pump with a compliance chamber, a blood pump with an isolated blood sac and accumulator, or a volume‐compensated blood pump. Most experimental studies designed to investigate this problem have been performed with compliance chambers. An ideal compliance chamber should accept 100 ml gas with less than a 15‐mm Hg increase in pressure and should automatically compensate for changes in atmospheric pressure. To date, two designs have been shown to be effective in laboratory and animal studies: a collapsible rectangular sac design developed by our group, and a lenticular chamber developed by Nose and associates. Compliance chambers of the former design have now been employed to provide the required compliance for motor‐driven assist pumps in long‐term calf studies.
Hemodialysis of Doxepin and Desmethyldoxepin in Uremic Patients
Authors: Faulkner R. D. , Senekjian H. O. , Lee C. S.
Published: November 2008

Abstract: The disposition of doxepin and its active metabolite desmethyldoxepin was investigated in five uremic patients undergoing hemodialysis. The hemodialysis system yielded a mean extraction efficiency of 7.6% for doxepin and 13.9% for desmethyldoxepin. Mean dialysis clearances were 10.8 and 18.1 ml/min for doxepin and desmethyldoxepin, respectively. The drug and metabolite recovery constituted a very small fraction of the body store, i.e., <1%. Hemodialysis did not significantly alter the plasma half‐life of doxepin, 14.6±4.3 h, or of desmethyldoxepin, 25.4±5.5h. The nondialyzability of both compounds could be attributed to the compounds' protein binding and volume of distribution. The dialysis experiments show that modification of the usual dosage regimen is not necessary during hemodialysis or on dialysis days. The dialysis parameters confirm that hemodialysis is not likely to be of value in the management of acute doxepin poisoning.
Removal of Inhibitors of Brain Na+, K+‐ATPase by Hemoperfusion in Fulminant Hepatic Failure
Authors: Seda H. W. M. , Hughes R. D. , Gove C. D. , Williams R.
Published: November 2008

Abstract: Serum from patients with fulminant hepatic failure inhibits rat brain Na+, K+‐ATPase activity in vitro. The effect of hemoperfusion on the level of inhibition was investigated with both resin and charcoal columns in clinical use. In the patient perfusions, the mean inhibitory activity of serum fell from 34.7±1.6 (SE) to 20.9±1.5% compared with pooled control serum when a resin column was used for the first time and from 26.9±2.2 to 20.4±1.7% with charcoal hemoperfusion, a statistically significant (p < 0.01) removal in both groups. Column chromatography on Sephadex G‐25 of material eluted from the resin column post‐hemoperfusion and of serum ujtrafiltrates before and after in vitro adsorption with charcoal showed considerable overlap in the profile of the substances removed, but with some peaks removed by only one adsorbent. Combinations of resin and charcoal in one hemoperfusion should remove a wider range of potentially toxic substances.
A Cardiac Output Monitor and Diagnostic Unit for Pneumatically Driven Artificial Hearts
Authors: Willshaw Peter , Nielsen Steve D. , Nanas John , Pichel Ricardo H. , Olsen Don B.
Published: November 2008

Abstract: The pneumatic artificial heart uses a flexible diaphragm to separate blood from air. The air space behind the diaphragm is connected to the atmosphere during diastole. Blood entering the heart during diastole displaces an equal volume of air into the atmosphere. A pneumotachograph is used to sense this flow of air. Integration of the airflow signal with respect to time yields the volume of air displaced during diastole, which is equal to the volume of blood entering the heart over the same period. This measured filling volume is equal to the cardiac output when averaged over a number of cardiac cycles. Allowance is made for regurgitant losses owing to the prosthetic heart valves. The output of the pneumotachograph is independent of absolute pressure, and so the device may also be used during the systolic (air compression) phase of the cardiac cycle. Analysis of the display of the airflow curves during diastole and systole has great diagnostic value. This device is accurate, easy to calibrate, stable, noninvasive, and does not require modification of any existing air‐driven artificial hearts.
Doppler Ultrasonic Detection of Particulate Release During Hemodialysis with Cellulose Hollow‐Fiber and Sorbent Suspension Reciprocating Dialyzers
Authors: Badylak Stephen F. , Ash Stephen R. , Thornhill Jerry A. , Carr David J.
Published: November 2008

Abstract: Doppler ultrasound is a noninvasive technique for monitoring moving objects such as flowing blood while ignoring stationary objects such as shunt tubing. A Doppler system was investigated to determine its sensitivity in detecting particulate release in blood during hemodialysis. Seven hemodialysis procedures with dogs and six trials with humans were done using a sorbent suspension reciprocating dialyzer (SSRD). Two additional trials were done with humans using a cellulose acetate hollow‐fiber dialyzer (HFD). A large increase (approximately twofold) was found in the reflected Doppler signal in outflowing blood from the SSRD and HFD in both dogs and humans. Numerous additional studies to characterize the nature of the particulate matter showed platelet aggregates in the dogs and fibrinogen‐fibrin degradation products in the humans to be present in the outflowing blood. In vitro studies suggested microscopic air bubbles (<25μm in diameter) may have contributed to the particulate matter detected during hemodialysis by this sensitive monitoring system.
Mechanisms of Acute Allergic Reactions
Authors: Hamilton Robert G. , Adkinson N. Franklin
Published: November 2008

Abstract: Acute allergic reactions range from mild conditions of local tissue swelling and pruritis to severe multisystem syndromes including asthma, urticaria and/or angioedema, gastrointestinal distress, and vascular collapse. Such reactions share a common pathophysiology characterized by vasodilation and postcapillary permeability, resulting in increased extravasation of fluid within minutes after exposure to an eliciting substance. Smooth muscle contraction of the respiratory or gastrointestinal tracts may also be involved. Most of these changes can be explained by the release of chemical mediators from circulating basophilic leukocytes and tissue mast cells. Human basophils and mast cells can be activated to release chemical mediators by several known pathways: crosslinking by allergens of specific immunoglobulin E antibodies attached to basophils and mast cells; anaphylatoxin formation following immune complex activation of the classical complement pathway; anaphylatoxin formed from direct activation of the alternative complement pathway by negatively charged surfaces; non‐complement, non‐antibody‐mediated direct histamine release; and idiosyncratic mechanisms involving physical exercise, psychological stress, or aspirin intolerance. Any or all of these mechanisms could be operative in patients experiencing acute allergic reactions at the commencement of hemodialysis.
Immunologic Studies of Hollow‐Fiber Dialyzer Extracts
Authors: Butcher Brian T. , Reed Margaret A. , O'Neil Carol E. , Leech Stephen , Pearson Frederick C.
Published: November 2008

Abstract: Testing failed to detect free isocyanates in dialyzer rinses or significant levels of immunoglobulin E antibodies to isocyanate‐protein conjugates in the serum of individuals reacting during hemodialysis with dialyzers containing Cuprophan membranes. Extended immunization of rabbits with Limulus lysate‐reactive material from dialyzer rinses demonstrated antigenic activity of the rinse that appears to originate from cotton linters used in hollow‐fiber membranes. The possibility that an immunologic response to these antigens may be a mechanism in adverse reactions to hemodialysis is discussed.
Quantitative Approach to Determine the Application Time of the Left Ventricular Assist Device
Authors: Inou Norio , Fujimasa Iwao , Imachi Kou , Miyamoto Akira , Nakajima Masaharu , Takido Naondo , Mabuchi Kunihiko , Tsukagoshi Shigeru , Kouno Akimasa , Atsumi Kazuhiko
Published: November 2008

Abstract: This study was designed to establish a method for determining the optimal time of the application of the left ventricular assist device from the viewpoint of the metabolism of the vital organs. Quantitative systemic low flow states were made utilizing goats with total artificial hearts. During these experiments, arterial lactate and pyruvate values were sequentially measured. The behavior of anaerobic metabolism during low cardiac output states and in the recovery process following normalization of the cardiac output was quantitatively described and evaluated. The experimental results are summarized as follows: If a time when the decay of arterial lactate ceases at a level above the normal level by >30 mg/dl is observed despite the use of intraaortic balloon pumping, that time is the exact optimal time for application of the left ventricular assist device. There is a great possibility that circulatory failure will be irreversible if left ventricular assist pumping is not initiated before the arterial lactate value increases to >140 mg/dl. The method of evaluating the alteration of anaerobic metabolism described in this study is useful for determining the application time of the left ventricular assist device.
Action on Mitochondrial Calcium Metabolism of an Ionophorous Compound Isolated from Uremic Plasma or Normal Urine
Authors: Fournier Nancy , Gallice Philippe , Crevat Aimé , Murisasco Antoine , Ducet Gaston , Elsen Raymond
Published: November 2008

Abstract: An ionophorous compound that is one of the uremic middle molecules is able to inhibit the mitochondrial storage of calcium. Its active concentration is equivalent to that found in uremic plasma. This result can explain the diminution of phosphate calcium granules observed in mitochondria from uremic children. Moreover, this phenomenon may be involved in the calcium pool decrease observed in chronic renal insufficiency.
Evaluation of the Thrombogenicity of Selected Microporous Oxygenator Membranes
Authors: Knight Patricia M. , Lyman Donald J.
Published: November 2008

Abstract: A comparative study of the thrombogenicity of several microporous membranes was performed using an ex vivo system simulating the conditions in an artificial lung. A study of platelet adhesion and adsorbed protein layer indicated that the membranes separated into three groups. Copolyurethane membranes adsorbed very few platelets and appeared to be most compatible; microporous polypropylene and polytetrafluoroethylene membranes were intermediate in their response; silicone rubber and silicone rubber‐coated paper membranes showed numerous platelet clots, often involving neutrophils and fibrin, and were the least blood compatible.
Paraproteinemia Associated with Demyelinating Polyneuropathy or Myositis: Treatment with Plasmapheresis and Immunosuppressive Drugs
Authors: Kiprov Dobri D. , Miller Robert G.
Published: November 2008

Abstract: Four patients with chronic, progressive demyelinating peripheral polyneuropathy were found to have paraproteinemia. Two of the patients had multiple myeloma [both immunoglobulin (Ig)G lambda]. The other two had benign gammopathies: one of IgG kappa type and the other one with marked polyclonal elevation of IgM. Immunofluorescence studies revealed deposits of the abnormal serum immunoglobulin along the myelin sheaths in two of the patients in whom sural nerve biopsies were performed. All four patients were treated with plasmapheresis in combination with immunosuppressive drugs. Favorable responses to the therapy was observed in all four patients, but the degree of response varied from patient to patient. Two patients who presented clinical and electromyographic findings consistent with polymyositis were found to have serum IgG kappa M components. Immunofluorescence studies performed on muscle biopsy material from both patients revealed deposits of the abnormal serum paraprotein along the sarcolemmal basement membrane. A treatment course of plasmapheresis and immunosuppressive drugs resulted in a sustained increase of muscle strength in both patients.
Orthotopic Heart Replacement by Nonpulsatile Axial Blood Pumps
Authors: Unger F. , Schistek R. , Hager J. , Roller I. , Nessler N. , Oberwalder P. , Benzer A.
Published: November 2008

Abstract: In the last decade, there have been many experiments with nonpulsatile blood pumps to perform functional heart replacement by biventricular assist devices. To determine if life is sustainable with nonpulsatile blood flow, two nonpulsatile blood pumps were implanted in the orthotopic position as an artificial heart after removal of the natural heart in extracorporeal circulation. In three preliminary experiments, the feasibility of total heart replacement with nonpulsatile implantable blood pumps was shown.
Technical and Clinical Data on High‐Performance Hemofiltration: Twelve Patients During One Year
Authors: Haas T. , Dongradi G. , Villeboeuf F. , de Viel E. , Verrier J. , Hillion D.
Published: November 2008

Abstract: In 12 chronic hemodialysis patients, postdilutional hemofiltration (HF) was substituted for conventional acetate hemodialysis (HD) (4–5 h/session with high‐area capillary dialyzers). In HF, the purposes were to obtain (a) no increase in pre‐HF uremia compared with pre‐HD uremia (high ultrafiltrate volume), (b) an HF duration shorter than that of HD (mean ultrafiltrate rate >120 ml/min), (c) a disposable cost of an HF session identical to that of an HD session (reuse of hemofilters and extemporaneous preparation of substitution fluid). One‐year results were (a) an ultrafiltrate volume of 26.8 L/session and a pre‐HF uremia of 35.4 mmol/L (pre‐HD uremia 34.0 mmol/L), (b) a mean ultrafiltrate rate of 143 ml/min and a mean HF duration of 190 min (mean HD session duration 250 min), and (c) better clinical tolerance and vascular stability in HF than in HD (weight loss 3.5 kg in HF and 3.0 kg in HD). Reuse of Filters and extemporaneous preparation of substitution fluid were not responsible for any pyrogen reaction or bacterial contamination. In conclusion, (a) compared with conventional HD, high‐flux HF results included identical removal of small molecules, improvement in vascular stability, decrease in session duration, and identical disposable cost; (b) routine high‐flux HF is workable in a dialysis unit; (c) vascular access is the most important limiting factor to high‐flux HF. Today 30–40% of patients can be treated with this method.
Mass Transfer Characterization of a New Polysulfone Membrane
Authors: Schneider H. , Streicher E.
Published: November 2008

Abstract: A new polysulfone capillary membrane has been tested ex vivo for its clearance performance under diffusive, combined diffusive and convective, and pure convective solute mass transfer. As was expected, increasing convective mass transfer produced augmentation only of clearances of high molecular weight solutes, and to a much lesser extent than reported for other membranes. This behavior is explainable by the enormous diffusive clearance capacity of the new membrane, which nearly reaches its theoretical maximal value, as derived from a computer model. Based on the very high hydraulic permeability, which makes this membrane equally suitable for filtrative and diffusive procedures, no membrane solute retention was found up to a molecular weight of 5,000 daltons. Stable hemocompatibility parameters (leukocytes, thrombocyte, and complement measurements) demonstrated absence of activation by this membrane during treatment. It is concluded that since its clearance performance is near the theoretical maximal and it shows superior biocompatibility, the membrane exhibits negligible interaction with the transported solutes independent of the transport mode.
Hydraulic Driving Unit and Control System for Artificial Hearts
Authors: Nessler Norbert H. , Schistek Roland , Hager Josef , Koller Ingrid , Gornik Erich , Unger Felix
Published: November 2008

Abstract: A driving unit for artificial ventricles was constructed in which the power transmission is hydraulic. This avoids the danger of an air embolism, which is characteristic of pneumatic drives in the case of membrane rupture. An electromagnet as a power source drives a rolling membrane pump to move the transmission fluid to the artificial ventricle. This incompressible connection allows direct control of membrane motion and pumped blood volume simply by measuring the armature stroke. The volume‐controlled mode is characterized by automatic self‐regulation according to Starling's law and self‐synchronization when the drive is used as a left (or right) ventricular assist device. Several measures were taken to increase the operational safety. The hemodynamic efficiency of the drive was tested in a number of in vivo experiments. The long‐term stability was proven in a 12‐month durability test.
Effect of Age on Calcification of Poly(hydroxyethyl methacrylate) in Animals
Authors: Imai Yohji
Published: November 2008

Abstract: The effect of age on the calcification of bio‐materials was studied by the subcutaneous implantation of poly(hydroxyethyl methacrylate) hydrogel in rats. The hydrogel sheets were implanted in rats 6, 12, 24, and 52 weeks (1 year) of age. The retrieved implants were compared and the percentage weight increase by mineralization was determined quantitatively. Significant differences in the rate and amount of calcification were observed between the growing (6 weeks old) and the adult (≥12 weeks of age) rats. The onset of calcification in the adult rats was significantly delayed. The immature rats had deposits three to four times as heavy as the mature rats.
Anatomicomechanical Study for the Hydraulic Line of a Thermal Left Ventricular Assist System
Authors: Sato Noashi , Snow Jeffrey , Harasaki Hiroaki , Smith William A. , Kiraly Raymond J. , White Maurice A. , Nosé Yukihiko
Published: November 2008

Abstract: A thermal left ventricular assist system currently under development consists of two separate major components, i.e., a pump/actuator module and an engine/ thermal battery module. The possible implantation site of the engine/battery module is tentatively determined to be the iliac fossa, which requires a flexible interconnecting line to the pump/actuator module. A quantitative and bio‐mechanical study was done on the effect of the implanted hydraulic line on the bendability of the torso. It revealed that the semirigid interconnecting line would not severely restrict the movement of the patient provided it has the proper prebend configuration. The cadaver fitting study proved the anatomical feasibility of the retroperitoneal iliac fossa as the implant site of the Thermal Ventricular Assist System 8 (TVAS 8) engine/battery module. The location and configuration of the interconnecting line of the TVAS 8 were determined using biomechanical analysis so that the restriction of the body movement due to the line could be minimized. The main route of the line was the left side of the trunk, and the lien is W shaped in configuration. The line elongation is the most critical resistive factor and accordingly there may still be rigidity during lateral flexion.
Use of the Anaerobic Threshold for Evaluating Various Total Artificial Heart Control Algorithms in Calves
Authors: Yozu R. , Shimomitsu T. , Jacobs G. , Watanabe T. , Morimoto T. , Stacy G. , Nosé Y.
Published: November 2008

Abstract: In the total artificial heart (TAH) project, choosing the best control mode is an important factor in the design of a completely implantable TAH. Four different control modes for the TAH were evaluated in the same calf using the anaerobic threshold (AT) as an assessment of aerobic capacity, where AT was defined as the oxygen consumption (vo2) at which the relationship between blood lactate measurements and vo2 became nonlinear during progressive treadmill exercise. This new approach tests the integrated response of the central, peripheral, and metabolic regulatory mechanisms to physiological workloads. Preliminary data showed AT in the left master alternatively ejecting mode to be slightly higher than in the other three modes.
Effect of Shear Rate on Clot Growth at Foreign Surfaces
Authors: Hashimoto Shigehiro , Maeda Hiroyoshi , Sasada Tadashi
Published: November 2008

Abstract: The hydrodynamic effect on clot growth at foreign surfaces was investigated quantitatively in vitro. Shear rates from 2 to 1,000 s‐1 were applied to a blood sample contained in a cone and plate viscometer. Four different artificial materials were used for cone and plate combination, namely, stainless steel, polytetrafluoroethylene, polycarbonate, and polymethylmethacrylate. Evaluation of clot growth was derived from the clotting ratio (the volumetric fraction of clot in the whole blood), which was experimentally determined from the rate of increase of frictional torque between the rotating cone and the stationary plate. The results show that the clotting ratio decreases markedly as the shear rate increases to 400 s‐1, regardless of material used. This study demonstrates that at a shear rate of>400 s‐1, clot growth at foreign surfaces is considerably inhibited.
Immunological Monitoring of Plasma Exchange in Primary IgA Nephropathy
Authors: Coppo Rosanna , Basolo Bruno , Roccatello Dario , Giachino Osvaldo , Lajolo Donatella , Martina Guido , Rollino Cristiana , Amore Alessandro , Costa Maria , Piccoli Giuseppe
Published: November 2008

Abstract: Plasma exchange (PE) has recently been proposed for primary immunoglobulin (Ig)‐A nephropathy (PIgAGN) with progressive course. To develop suitable guidelines for PE in these cases, the authors evaluated the clinical usefulness of some immunological parameters in five patients with PIgAGN treated with PE combined with immunosuppressive drugs and small doses of corticosteroids. These parameters included the levels of IgA‐containing immune complexes (IgAIC) by a specific conglutinin assay, the function of the mononuclear phagocyte system (MPS) by the in vivo clearance of IgG‐sensitized erythrocytes, and complement activation as determined by C3d measurement. HLA types were also determined. Three patients had an acute nephritic syndrome with a rapidly progressive course, one of them showing sclerotic histologic changes. The two other cases had a relentless progression toward renal failure. In the patient with sclerotic PIgAGN, the MPS function was normal and the IgAIC and C3d levels were low throughout the treatment. In the other four cases, the high IgAIC and C3d levels and the MPS dysfunction found before treatment markedly improved after several PEs. The immunological parameters remained normal during the post‐PE follow‐up in two cases with acute nephritic syndrome and rapidly progressive course, but worsened again in two cases with a relentless course, particularly in one who possessed the B8/DR3 HLA type. Immunological monitoring including IgAIC, C3d, and MPS function is proposed, in addition to histological and clinical evaluation, as a guideline for PE in PIgAGN with evolving course.