bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid Artificial Organs: Are They Really Necessary?
Authors: Nosd Yukihiko , Malchesky Paul S. , Smith James W.
Published: July 2010

In order to reproduce completely the function of an organ, past research has considered hybrid artificial organs as the only method to achieve this goal. Various attempts have been made to use cell components, whole cells, tissue, and organ sections in conjunction with artificial organ systems. However, utilization of biological preparations or tissues is not clinically practical today. In this paper disadvantages of using natural tissue preparations are outlined. Recent progress in membrane technology such as membrane plasmapheresis, particularly on‐line plasma treatment by multiple reactors, on‐line plasma treatment by cryogelation, or the use of a cascade membrane scheme for the selective removal of macromolecules, will provide the tools to treat and remove macromolecules which were once considered extremely difficult to treat. The historical development of membrane plasmapheresis is described, including potential applications of this type of artificial organ for practical clinical treatment of metabolic, toxic and immunologic disease states.
Extracorporeal Liver Perfusion in the Treatment of Acute Hepatic Failure
Authors: Tung L.C.
Published: July 2010

Twenty‐three extracorporeal liver perfusions have been performed for the treatment of hepatic coma in 13 patients. No improvement was found in four patients, improvement in nine. Six of these nine patients recovered full conciousness. All seven patients with pre‐existent liver disease died. Of six patients without pre‐existent liver disease, three were discharged and are still alive. At present, extracorporeal liver perfusion seems to be a promising treatment for hepatic coma. It should be undertaken at stage IV and at stage 111 with increasing prothrombin time. Pre‐existent liver disease should be excluded beforehand by laparoscopy.
Hemoperfusion Over Small Liver Pieces for Liver Support
Authors: Kimura K. , Gundermann K. J. , Lie T. S.
Published: July 2010

In order to develop a liver support system using a device with a simple technique, hemoperfusion was performed with pig livers obtained freshly or preserved by freezing in the form of 5‐mm cubic pieces. In the fresh liver pieces, the amount of ATP increased significantly from 0.080 to 0.266 μmol/gm wet weight (P<0.025) 120 min after the start of perfusion. The concentration of ammonia in the perfusate with fresh liver pieces was remarkably lower than controls (P<0.001) even immediately after the first ammonia load. It remained unchanged afterward despite two additional loads. The frozen liver pieces removed 83% of the bilirubin load (P<0.001) during the perfusion. It is suggested that not only the fresh liver pieces but also the frozen liver pieces are effective for hepatic assist.
Alteration of Human Leukocyte Chernotaxis, Chemiluminescence, and HMP Shunt Activity Caused By Mechanical Trauma
Authors: Dewitz T.S. , McIntire L.V. , Martin R.R.
Published: July 2010

The effect of graded shear stress exposure (0 to 800 dynes/cm2 at 35°C) on human leukocyte function was examined in vitro, using a concentric cylinder viscometer. Boyden Chamber chemotaxis was significantly reduced at stress levels above 150 dynes/cm2, and was over a factor of three lower after exposure to trauma levels of 450 dynes/cm2 Hexose monophosphate (HMP) shunt activity following particle ingestion was also significantly lower after exposure to shear stresses of 150 dynes/cm2 or more for ten minutes. PMN chemiluminescence was reduced following stress trauma of 450 dynes/cm2 using whole blood, and after 150 dynes/cm2 using leukocyte suspensions. All the functional alterations reported appear to be bulk shear stress effects and not due to surface interaction, as changing the surface‐to‐volume ratio in the viscometer by over a factor of three did not change the damage caused at a given stress level. These functional alterations caused by mechanical trauma may be important in hemodialysis, cardiopulmonary bypass, venovenous perfu‐sion, and in any blood‐contacting artificial organ. The stress levels required for damage are of the same order as those required for platelet functional alteration, and much lower than those required for erythrocyte hemolysis for the same exposure times.
Sorbent Membranes: Determination of Sorption Capacity and True Membrane Permeability
Authors: Ozdural Ahmet R. , Pişkin Erhan
Published: July 2010

Sorbent membranes are designed to meet the requirements for extracorporeal treatment of body fluids. These membranes offer the possibility of combining hemodialysis and hemoperfusion in a single device. Transport of solutes with both sorption and dialysis occurs simultaneously in a sorbent membrane dialyzer. In an effort to determine the sorption capacity and true membrane permeability (by dialysis only) of sorbent membranes, in vitro data were obtained for creatinine. The individual effects of dialysis and sorption on the rate of removal of solutes and their dependence upon flow rate in a sorbent membrane dialyzer were determined from the data of solute vessel concentration vs time. Experiments were carried out with a continuous flow, flat‐plate dialyzer and Enka AG sorbent membranes have been selected for evaluation. It was found that sorption plays an important role in the creatinine removal. However, as the time increases, sorption becomes relatively less important and the creatinine removal becomes dominated by dialysis.
A Reciprocating, Single‐Needle Hemodialyzer with Bidirectional Flow of Sorbent Suspension
Authors: Barile Ronald G. , Wang Nien‐Hwa L. , Blake Donald E. , Belcastro Patrick F. , Gupta Shri , Regnier Fred E. , Thornhill Jerry A. , Kessler David P. , Ash Stephen R.
Published: July 2010

Previous theoretical analysis has indicated that adequate mass transfer is possible in a dialyzer with reciprocating membrane motion provided that the dialysate concentration of uremic substances is kept low. Earlier models have utilized a collection of sorbents (charcoal, urease, and a cation exchanger) constrained next to the dialyzer membranes. We have designed a new dialyzer with a sorbent suspension having free access from a reservoir to the spaces between membrane packages. At a treatment rate of 150 ml/min/m2, the in vitro creatinine clearance is 75 ml/min/m2, which agrees within experimental accuracy with the theoretical prediction. The creatinine clearance, flow resistance, and compliance of the dialyzer are constant during four to six hours of testing. In vivo tests have been performed during urea and creatinine infusion in a normal dog and in a dog with 3/4 nephrectomy. The in vivo creatinine clearance agrees within 10% with the in vitro clearance. Sodium, potassium, calcium, and bicarbonate fluxes are acceptable for patients in renal failure. The new design allows a higher capacity for urea and creatinine, since larger amounts of sorbent may be used.
Coating Membranes for a Sorbent‐Based Artificial Liver: Adsorption Characteristics
Authors: de Koning Henk W. M. , Chamuleau Rob A. F. M. , Bantjes Adriaan
Published: July 2010

Techniques are described for the coating of sorbents to be used in an artificial liver support system based on mixed sor‐bent bed hemoperfusion. Activated charcoal has been coated with cellulose acetate (CA) by solvent evaporation. With Amberlite XAD‐4, the Wurster technique was used for coating with CA. XAD‐4 has also been coated with a synthetic poly‐electrolyte with anticoagulant activity by adsorption and fixation by gamma radiation‐induced crosslinking. Activated charcoal, XAD‐4, and a cation exchange resin, all in powdered form, were encapsulated in agarose gel beads. Adsorption characteristics onto the sorbents are described. The results are in agreement with a theoretical model presented. In general, adsorption onto XAD‐4 is limited by film diffusion. With activated charcoal, pore diffusion limitation is generally observed. Blood compatibility is improved by coating.
Arterial Pressure: Its Role in Perfusion and as a Criterion of Extracorporeal Circulation Adequacy
Authors: Osipov Valentin P. , Khodas M. J. , Dementjeva I. I. , Pjatnitskaja G. Kh.
Published: July 2010

Thirty‐five patients undergoing open‐heart surgery are reported. Cardiac index, mean arterial pressure, oxygen consumption, lactate, pyruvate, and lactate excess in the blood were measured. An inverse correlation of arterial pressure with oxygen consumption and lactate excess was found during perfusion. Comparison of those parameters with hemodynamic and metabolic data before perfusion demonstrated that, even prior to extracorporeal circulation, lactate and lactate/pyruvate ratio affect cardiac index. These parameters determined the level of “hypoxic” lactate concentration as well as arterial pressure during perfusion.

These data appear to suggest that during perfusion the severity of metabolic disturbances determines the level of arterial pressure rather than vice versa. Arterial pressure and oxygen consumption, thus, cannot be applied as general criteria of the adequacy of extracorporeal circulation.
A Method for Temporary Complete Substitution of Gas Exchange Function of the Lung
Authors: Osipov Valentin P. , Efuny Sergei , Lurie Gennady , Knjazeva Galina , Saveljev Sergei , Jushkov Mark , Mosolova Larisa
Published: July 2010

Total substitution of lung gas exchange function can be achieved by oxygenating all blood in a heart‐lung machine and requires thoracotomy. In accordance with calculations based on physical principles, if extracorporeal oxygenation is combined with barometric pressure raised to 3 atm, half of the cardiac output will suffice to maintain normal blood oxygenation. Excessive amounts of oxygen dissolved in blood passed through an oxygenator will suffice for the total oxygenation of the rest of the blood.

This assumption was investigated in 15 experiments on dogs and one human patient in a hyperbaric chamber. The bubble oxygenator and pneumatic membrane pumps were used. The results suggest that this method of total substitution of lung gas exchange function is feasible. This technique does not require thoracotomy and can be carried out on a patient in any position on the operating table. This method can be used during bronchoscopy treatment, lung lavage, and trachea surgery.
Severe Reactions to Cuprophan Capillary Dialyzers
Authors: Popli Subhash , Ing Todd S. , Daugirdas John T. , Kheirbek Ali O. , Viol Geoffrey W. , Vilbar Remegio M. , Gandhi Vasant C.
Published: July 2010

Five severe reactions occurred in four maintenance hemodialysis patients 1 to 5 minutes after initiating dialysis with Cuprophan capillary dialyzers. All reactions were life‐threatening and one resulted in death. Inadequate rinsing of the dialyzers was probably the cause of the reactions. The severe reactions were managed by immediate discontinuation of dialysis and the institution of supportive treatment. Antianaphylactic measures were also attempted, but their therapeutic effectiveness remains to be determined.
Storage of Silicone Particles in Macrophages: An Iatrogenic Complication in Dialysis Patients
Authors: Bommer J. , Ritz E. , Waldherr R. , Gastner M. , von Sonntag C.
Published: July 2010

Foreign body substances consisting of silicone particles released from tubing during exposure to roller pumps were demonstrated in the viscera of several dialysis patients at autopsy and in vivo. The material was identified by light microscopy, transmission electron microscopy, and scanning electron microscopy with electron beam microanalysis. Potential clinical consequences include hepatosplenomegaly, non‐A, non‐B hepatitis, and hypersplenism. Potential immunological and cardiogenic hazards cannot be currently assessed.
In Vitro Maintenance of Terminal‐Differentiated State in Hepatocytes Entrapped Within Calcium Alginate
Authors: Miura Yoshiharu , Akimoto Toshihiko , Fuke Yuko , Yamazaki Sene , Yagi Kiyohito
Published: July 2010

Abstract: In cultured hepatocytes entrapped within Caalginate, liver‐specific functions such as induction of tyrosine aminotransferase and serine dehydratase were stimulated by increasing the cell density. In contrast, a growth‐related function such as induction of glucose‐6‐phosphate dehydrogenase was strongly stimulated by decreasing the cell density. This reciprocal regulation was mimicked by the addition of plasma membranes purified from adult rat liver to entrapment cultures at low cell density. Also, gluconeogenesis from lactate was stimulated by the addition of epinephrine (α,β‐agonist) with propranolol (β‐blocker). These results suggest that entrapped hepatocytes maintain not only terminal‐differentiated state but also α‐adrenergic response as shown in vivo.
Immunosorbent Chemistry: A Study of Agarose‐Based Column Sorbents for the Removal of Low‐Density Lipoprotein (LDL) from Blood
Authors: Ostlund Richard E.
Published: July 2010

Abstract: Anti‐LDL antibody was covalently attached to agarose beads in order to prepare an immunosorbent for the removal of LDL from plasma or blood. Both the conditions of antibody coupling and the type of agarose matrix used were critical to the optimization of LDL binding capacity. Sorbents binding 6–8 mg lipoprotein cholesterol/ml column volume were obtained using cyanogen bromide or glutaraldehyde coupling procedures and crosslinked 2% agarose beads. The sorbent could be regenerated by washing with 1 M acetic acid, a reagent that was also an effective disinfectant. In vitro perfusions of whole blood over small columns of 212–300 μ beads showed excellent flow rates (2 ml/min/cm2 under 50–100 cm saline pressure); recovery of leukocytes and platelets exceeded 90%, and complement was not activated. Leakage of antibody and bead matrix was negligible. The antibody‐agarose beads could not be sterilized by conventional techniques, but withstood treatment with 0.34% phosphoric acid in 80% ethanol at 37°C, a novel method of chemical sterilization.
Percutaneous Intraaortic Balloon Pumping: Four Years from Tiblisi
Authors: Bregman David
Published: July 2010

Abstract: Intraaortic balloon pumping (IABP) has now evolved as the mechanical supportive treatment of choice for the management of refractory left ventricular power failure. A new single‐chambered percutaneous intraaortic balloon (Datascope Corp., Paramus, NJ, U.S.A.) has been constructed around a central guidewire. The balloon can be wrapped around the guidewire, enabling its insertion into the femoral artery through a 12‐F sheath, inserted by a modified Seldinger technique. A dual‐lumen automatic wrapping version has recently been employed. Percutaneous IABP insertion has been performed in 149 patients (mean age 58 years). In our medical group of 75 patients, 59 underwent urgent open heart surgery and 53 (90%) survived. In patients who could not be separated from cardiopulmonary bypass, 23 of 61 (38%) survived. Vascular complications occurred in 10% of the patients. Percutaneous balloon insertion permits the rapid institution of IABP support and broadens the medical and surgical applications of IABP.
Failure of Platelet Markers to Evaluate Membrane Biocompatibility During a Combined Hemodialysis‐Hemoperfusion Treatment
Authors: Buccianti G. , Giaretto S. , Pogliani E. M. , Lorenz M. , Valenti G. , Bianchi M. L. , Cresseri D.
Published: July 2010

Abstract: Plasma levels of the platelet markers β‐throm‐boglobulin (β‐TG) and platelet factor 4 (PF4) are among the most sophisticated indexes of biocompatibility available to evaluate new members for hemodialysis. This investigation was designed to determine the extent of platelet activation by measuring the α‐granule release products, β‐TG and PF4; anticoagulation and thrombo‐genesis by monitoring plasma heparin; and fibrinopeptide A (FPA) and thromboxane B2 (TX B2) levels during treatment with a combined hemodialysis‐hemoperfusion system. Both in vivo and in vitro results showed that the platelet markers had a pattern different from that generally observed during treatment with hemodialysis alone. This is due to the avidity of charcoal for the markers studied, which therefore cannot be used to evaluate the biocompatibility of the system.
Hemofiltration and Plasmapheresis in Premature Infants and Newborns
Authors: Bambauer Rolf , Jutzler Gustav Adolf , Philippi Horst , Jesberger Hans‐Jürgen , Limbach Hans‐Gerhard , Richter Joachim , Sitzmann Friedrich Carl , Pieroth Walter
Published: July 2010

Abstract: Extracorporal detoxication methods in newborns are most unavailable, contraindicated because of technical problems. Herein are reported the experiences with a blood pump unit that was miniaturized for hemodialysis, hemofiltration, and plasmapheresis in newborns. In three premature infants with acute renal failure of different etiology (two newborns with severe Rh‐erythro‐blastosis, 1 premature infant with hypoproteinemia) 13 single‐needle hemofiltrations and 6 single‐needle plasmaphereses were performed with double head pump, special tube systems, and small modules. The age of the patients ranged from 1 to 14 days, body weight was between 800 and 2,800 g. Four umbilical veins and two femoral veins were used as vascular access. The ultrafiltration rate during the treatment averaged 0.3 ml/min in single‐needle hemofiltration and the plasma filtrate flow rate 1.3 ml/min in single‐needle plasmapheresis. All treatments were well tolerated. Four patients died due to complications unrelated to the treatment, two patients recovered. These preliminary results show that both hemofiltration and plasmapheresis may be carried out without major problems in premature infants and newborns.
Percutaneous Access Devices in Calves Receiving an Artificial Heart
Authors: Holmberg David L. , Dew Pamela , Crump Carol , Burns Greg , Taenaka Yoshiyuki , Olsen Donald B.
Published: July 2010

Abstract: Vegetative endocarditis and thromboembolism are the two leading pathologic findings and causes of death in calves receiving total artificial hearts (TAH). Percutaneous access devices (PAD) for the pneumatic drive lines often become infected and may serve as the nidus of infection of the vegetative lesions. Observations of 80 calves living with TAHs revealed that most infections began at the dorsal surface of the PAD. Chronic skin ulceration or acute, traumatic avulsion can result in PAD separation from the skin and bacterial implantation. Evaluation of 58 necropsy specimens from calves with TAHs demonstrated improper flange positioning in 76% of the PAD and gross infection in 57%. A new implantation technique and design of PAD have resulted in better flange position and less irritation at the skin/device interface. Necropsies of 11 animals with the new PAD have shown a reduction in superficial infections.
Effect of Right Ventricular Bypass Peak Flow‐Rate on Intrapulmonary Shunt Ratio
Authors: Hashimoto Shigehiro , Moriya Hoshihito
Published: July 2010

Abstract: The effect of total right ventricular bypass peak flow‐rate on the intrapulmonary shunt ratio was quantitatively investigated in animal tests. To give variations in the peak flow‐rate (from pulsatile to intermediate to nonpulsatile), three types of blood pump (piston‐bellows, screw, and centrifugal) were applied to dogs. The intrapulmonary shunt ratio was calculated from blood oxygen content drawn every 30 min from the outlet of the right ventricular bypass pump and from the femoral artery, while the canine lung was ventilated with 100% oxygen gas by an artificial respirator. The results show that when the intrapulmonary shunt ratio ranged between 0.095 and 0.392 there is no clear relation to the peak‐flow‐rate index (which varied from 1.1‐17.0 1 min‐1 m‐2) over the preceding 30 min. This study demonstrates that the intrapulmonary shunt ratio is able to be kept within the range of control values for 6 h even with a peak‐flow‐rate index of < 4.01 min‐1 m‐2.
Method of Formation of Artificial Organ Components Using a Plastic Dispenser System Manipulated by a Robot
Authors: Togawa Tatsuo , Matsudaira Hiromichi , Hori Mitsuhiro , Tsuchiya Kiichi
Published: July 2010

Abstract: In order to produce an artificial organ component having a complicated structure, a plastic‐forming method was proposed in which small amounts of material were accumulated successively by using a dispenser system manipulated by a robot; a preliminary experiment with silicone rubber was conducted. Components of different shapes were produced, including straight tubes, tapered tubes, bifurcating tubes, tubes having leaflets on the inside, cones, spiral tubes, and tubes with a sack. This method provides the possibility of producing complicated artificial organ components, which are difficult to produce by conventional plastic‐processing methods.
Microcirculation and Artificial Heart Research
Authors: Lübbe Andreas Stephan
Published: July 2010

Abstract: Small blood vessels may play a more important role in artificial heart (AH) recipients than ever suspected before. Observations of elevated total peripheral resistance, low hematocrit, reduced oncotic pressure, high circulating blood volume, and arterial pulsations with nonpulsatile devices require consideration of peripheral vascular control mechanisms. Establishment of microcirculatory parameters could help in adapting cardiac output to different metabolic states. AH research offers the opportunity to evaluate pure microvascular effects of drugs without any cardiac influences. Furthermore, drugs could be developed to alter microvascular and hence, hemodynamic conditions in patients with AH. However, further development of microcirculatory techniques is imperative in order to examine small blood vessels in large animals or patients.
Improved Biocompatibility by Modified Cellulosic Membranes: The Case of Hemophan
Authors: Lucchi Leonardo , Bonucchi Decenzio , Acerbi Maria Angela , Cappelli Gianni , Spattini Andrea , Innocenti Maurizio , Castellani Alfonso , Lusvarghi Egidio
Published: July 2010

Abstract: The rising problem of biocompatibility is encouraging the development of new dialysis membranes, but the high cost of synthetic ones precludes their wide use. The authors compared the biocompatibility of cu‐prophan (CU), cellulose acetate (CA), and hemophan (HE), evaluating both in vitro and in vivo polymorpho‐nuclear leukocyte (PMN) oxidative metabolism activation by resting chemiluminescence and complement activation by C3a; in vivo PMN counts during dialysis were also performed. The lowest increase in in vitro PMN resting chemiluminescence using HE was +71.3% with CA, + 49.3% with CU, and +21.4% with HE (p < 0.001 versus CA and CU); furthermore, HE did not significantly stimulate PMN resting chemiluminescence during in vivo hemodialysis: +56.6% with CA, +38.8% with CU, and + 3.7% with HE (p < 0.01 versus CU and p < 0.001 versus CA). C3a concentration increased with all membranes both in vitro and in vivo, but HE (in both experimental conditions) showed the lowest increase at any time (p < 0.001 versus CA and CU). After 15 min of dialysis, PMN count dropped to 20.3% of basal values with CU, to 49.8% with CA, and to 76.5% with HE (p < 0.001 versus CU and CA). Among cellulosic membranes, HE is the most biocompatible and appears to be an important step in preventing blood‐membrane interactions and related complications.
An Economical New Process for Incenter Bicarbonate Dialysate Production: Comparison with Acetate in a Large Dialysis Population
Authors: Oettinger Carl W. , Oliver Jamie C.
Published: July 2010

Abstract: It is generally agreed that bicarbonate dialysate is preferable to acetate dialysate, but the major limiting factors of high cost and technical difficulty in maintaining its stability for prolonged periods preclude its widespread use. The procedure developed by the authors stabilizes bicarbonate dialysate for up to 4 days, rendering bicarbonate dialysate feasible for routine out‐patient use. HCO3 dialysate is produced in our dialysis unit after an initial investment of $10,000.00, at a cost per 4‐h treatment of $1.22 at a dialysate flow of 500 cc/min. One hundred fifty‐one chronic dialysis patients participated in an 18‐week study to evaluate clinical symptomatology when bicarbonate was substituted for acetate as the dialysis base buffer. Evaluation of each dialysis treatment (total of 8,183 treatments) consisted of both subjective and objective criteria (vomiting, angina, cramps, hypotension, and frequency of use of mannitol, hypertonic saline, and nitroglycerine). The patients were unaware of the change in dialysate solutions. There was a significant reduction (p < 0.001) in the incidence of vomiting, cramps, hypotension, nausea, flushing, and the use of mannitol and hypertonic saline during bicarbonate dialysate treatment compared with acetate dialysate. Shortness of breath, angina, mental confusion, and paresthesias were not statistically changed. Although the method of HCO3 dialysate production is associated with occasional higher bacterial count than currently recommended by AAMI standards, no adverse reactions were observed in patients treated with standard efficiency dialyzers. It is concluded that the process for incenter HCO3 production is safe, economical, and better tolerated than acetate dialysate.
Erythrocyte Destruction under Periodically Fluctuating Shear Rate: Comparative Study with Constant Shear Rate
Authors: Hashimoto Shigehiro
Published: July 2010

Abstract: The hydrodynamic effect of periodically fluctuating shear rate on erythrocyte destruction was quantitatively studied in vitro in comparison with constant shear rates. Uniform shear rates (< 1,000 s‐1; constant or sinu‐soidally fluctuating with time) were applied to heparin‐ized canine blood contained in the concavo‐convex type of Couette flow testing machine for (1.8–9.0) x 103 s at 24d̀C. The results show that the erythrocyte destruction (evaluated with hemolysis ratio; plasma hemoglobin count per whole blood hemoglobin count) decreases when the exposure time of larger (>500 s‐1) shear rates is interspersed with smaller (<300 s‐1) shear rates.
Hemostatic Abnormalities in Two Patients Implanted with Total Artificial Hearts
Authors: Al‐Mondhiry Hamid , Pierce William S.
Published: July 2010

Abstract: Patients implanted with total artificial hearts (TAH) suffer frequent thromboembolic complications. The authors report results of continuous monitoring of multiple hemostatic parameters and autopsy findings in two patients implanted with TAH. Case 1 who used a TAH for 10 days and then underwent orthotopic transplantation died of fungal infection 7 days later. At autopsy, mycotic and nonmycotic thrombi were found in the brain, kidneys, spleen, and large bowel. Case 2, who survived 396 days with a TAH, suffered multiple throm‐botic episodes despite adequate anticoagulation with warfarin. Autopsy revealed widespread thrombotic lesions mostly in the brain and lungs. Both patients had markedly elevated plasma β‐thromboglobulin and fibrinopeptide A levels throughout their survival, indicating sustained activation of platelets and coagulation secondary to blood contact with artificial surface. Other factors such as infection, liver damage, and acute pancreatitis might have also contributed to activation of hemostasis. As used in the authors two patients, antiplatelet drugs and warfarin seem to be ineffective in preventing artificial heart‐related thromboembolic complications.
Acetate‐Free Biofiltration: A Viable Alternative to Bicarbonate Dialysis
Authors: Santoro Antonio , Ferrari Giuseppe , Spongano Marco , Badiali Fabio , Zucchelli Pietro
Published: July 2010

Abstract: Eight patients were studied during four sessions of acetate‐free biofiltration (AFBF). AFBF is a new dialysis technique with no base replacement agents in the dialysate and with the addition in postdilution mode of bicarbonate (HCO3) solution directly into the extracorpo‐real blood circuit. In this study the effects on acid‐base balance of different infusions of sodium bicarbonate (NaHCO3) ranging from 751 to 1,002 mEq per session was evaluated. There were significant positive correlations between the HCO3 infused and net HCO3 gained (r = 0.776, p < 0.0001) and between HCO3 infused and plasma intratreatment HCO3 changes (n = 0.562, p < 0.001). Stepwise multiple linear regression analysis demonstrated that HCO3 infused and plasma predialysis HCO3 values played the major role in HCO3 balance in AFBF. The best correction of metabolic acidosis was obtained with the infusion of 900–1,000 mEq of HCO3. The use of substitution fluid with 145 mEq/L of Na concentration avoids the risk of a positive intratreatment Na balance.
Experimental Study on the Adsorption of Excess Heparin with Anion Exchange Resin Fiber
Authors: Matsuda Koichi , Oka Totaro , Tani Toru , Hanasawa Kazuyosi , Yoshioka Toyokazu , Aoki Hirohiko , Endo Yoshihiro , Ishii Yutaka , Numa Kenji , Kodama Masashi
Published: July 2010

Abstract: Anion exchange resin fiber (Ionex) was used as a heparin adsorbent. Ionex has the adsorption capacity of 70 mg/g (weight by desiccation) for heparin, and was used in an attempt to remove the heparin from blood‐perfused artificial organs, before the blood was transfused back into the patients. In the ex vivo study, the 5 systemically heparinized dogs (500 U/kg) were treated with a 35–40 g column of Ionex, by direct hemoperfusion (DHP). The concentration of heparin was significantly reduced, within 15 to 60 minutes, using the Ionex. This suggested the possibility of removing excess heparin from the living body. In in vitro, the relationship between the amount of heparin by Ionex and the blood‐flow volume were evaluated. Whole blood taken from dogs was added to 5 U/ml of heparin. This was then introduced into a small column containing 0.9 g Ionex, at blood‐flow rates of 0.8, 1.6, and 3.2 ml/min. A good adsorption capacity was shown at the blood‐flow rate of 0.8 ml/min. One possible explanation for this is that the heparin dispersed in the blood cells gradually was passed on into the plasma and, so, did not have time to be adsorbed at the faster flow rates.
Control of the Total Artificial Heart: New Aspects in Human versus Animal Experience
Authors: Schima Heinrich , Trubel Wolfgang , Coraim Farag , Huber Leopold , Müller Michael Rolf , Redl Gerhard , Losert Udo , Thoma Herwig , Wolner Ernst
Published: July 2010

Abstract: Control strategies for total artificial heart application have generally been based on experience with healthy animals. Human patients in a bad state of health who have impaired organ functions and who are subjected to intensive care procedures can develop atypical hemodynamic behavior. In these patients, both unstable and hyperstable behavior of the vascular resistance were observed. Therefore, regulation of cardiac output (CO) by pressure parameters only was avoided and CO was adjusted to obtain an appropriate O2‐utilization (O2U). Intending to keep the O2U within ranges of 20–25%, we obtained cardiac indexes between 3.3 and 4.4 L/m2/min (CO 6–8 L/min), which is higher than other cardiac indexes reported. A CO of 10.5 L/min was even necessary to obtain an O2U of 30% in a septic patient. This strategy caused a stable driving management and led to a rapid hemodynamic stabilization and general improvement of the patients' condition. Results indicate that it is also very important to monitor metabolic parameters for appropriate driver adjustment as well, especially in the early postoperative phase, and that O2‐U is a sensitive and useful parameter for this purpose.
Concentration Profiles of Platelet‐Sized Latex Beads for Conditions Relevant to Hollow‐Fiber Hemodialyzers
Authors: Waters Christopher M. , Eckstein Eugene C.
Published: July 2010

Abstract: A freeze‐capture method was used to obtain the concentration profiles of platelet‐sized latex beads (2.5 μm diameter) in saline‐based red cell suspensions flowing through tubes with inner diameters of 135 and 200 μm. Without red cells the concentration profile exhibited a slight deficit near the wall. For hematocrits from 15 through 52%, the concentration profile exhibited a near‐wall excess of beads, from two to eight times the central concentration. Near‐wall excesses were small or nonexistent in the first half centimeter of the tube. For hematocrits of 15 and 30%, the profile and near‐wall excess were equal at stations 2 cm or more from the entrance. These results suggest that there is a flow‐driven mechanism that moves platelet‐sized beads toward, but not to, the wall.
Cardiovascular Laser Application
Authors: Schaldach Max
Published: July 2010

Abstract: With the invention of the laser, many clinical disciplines have taken advantage of this new energy source. Its precision, intensity and energy density is superior to all other known surgical devices. Based on the principle of light amplification from a photon‐emitting resonator, the monochromaticity, collimation and coherence provide the high‐energy density of the laser beam for medical applications. The state‐of‐the‐art and future potential of laser use in cardiovascular diseases will be reviewed. Most of the work in this field has been accomplished during the past decade with numerous research projects. Although many technical advances have been made, so far the results in cardiovascular medicine are in the areas of vessel anastomosis, ablation of conduction passes for arrhythmia therapy, and angioplasty. In this paper, special attention will be given to the recent success in XeCl excimer laser application for photodecomposition of tissue with a goal of improved recanalization. The high‐power density of the XeCl excimer laser provides significant advantages for the disruption of both embolic and calcified plaque. Regardless of the type of tissue ablated, gross, histologic, and ultra‐structural analysis confirmed the absence of thermal injury in luminar recanalization as well as in animal studies. Progress in the manufacture of catheters, with multiple very small diameter fibers, led to the decisive breakthrough in clinical laser angioplasty. Peripheral as well as coronary arteries have been successfully recanalized followed by balloon dilatation. The ease of application and the success achieved thus far have resulted in an optimistic assessment for laser medicine.
Loss of Anticoagulant Effect of Heparin During Circulation of Human Blood In Vitro
Authors: Pijl A. J. , Solen K. A. , Mohammad S. F. , Monson R. , Yu L. S. , van Griensven J. M. T. , Olsen D. B. , Kolff W. J.
Published: July 2010

Abstract: Device‐induced thrombogenesis was studied in an in vitro model using human blood circulated through an artificial ventricle. A new constant pressure filtration technique was used to detect circulating microemboli, the activated partial thromboplastin time (APTT) test was used to monitor the blood for the presence of anticoagulant activity of heparin, and hemolysis was quantified by measuring the plasma free hemoglobin level. Circulation of blood through a 20‐ml stroke volume pneumatically driven ventricle for 6‐9 h resulted in a significant reduction of APTT, indicating the loss of the anticoagulant effect of heparin. Microemboli concentration was minimal until the APTT decreased below 125 s, at which time the microemboli concentration increased rapidly. This was presumed to be due to the formation of thrombi following a decrease in heparin activity. A significant increase in hemolysis was also noted when blood was pumped. None of these changes was noted in the nonpumped control blood. Spontaneous loss of heparin activity in blood circulated by a pneumatically driven pump may have clinical implications and may help understanding of the problems associated with device‐induced thrombogenesis.
Absence of Lung Reactions After Complement Depletion During Dialysis: An Experimental Study in Pigs
Authors: Blomquist Sten , Malmros Christer , Mårtensson Lena , Thörne Johan
Published: July 2010

Abstract: Sequestration of 111In–labeled neutrophils (polymorphonuclear leukocytes–PMNs) in the lungs during sham dialysis was studied dynamically using a gamma camera. Five animals were pretreated with cobra venom factor, naja naja (CVF), to achieve depletion of the complement system, mainly C5a. Seven animals were studied without pretreatment with CVF. Central hemodynamics and gas exchange were studied as well as neutrophil function using luminescence and aggregation. In the control group there was a significant sequestration of neutrophils in the lungs, which reached a maximum between 15 and 17 min after the start of hemodialysis. The peripheral neutrophil count decreased concomitantly. These changes were virtually absent in the CVF–treated group. PMN aggregation and luminescence were abolished in CVF–treated animals. Both pulmonary artery pressure and pulmonary vascular resistance increased significantly in the control group, whereas in the CVF group these parameters remained unchanged. There were no differences in blood gases, platelet count, or hematocrit between the groups. The results clearly indicate that the activation of neutrophils within minutes after the start of hemodialysis is greatly dependent on C5a activation because it can be abolished by C5a depletion. This activation is accompanied by changes in the pulmonary circulation with increases in pressure and resistance.
Hemostatic Alterations Caused by Ventricular Assist Devices for Postcardiotomy Heart Failure
Authors: Tanaka Kuniyoshi , Wada Kiyoto , Morimoto Tamoisu , Shomura Sekira , Nasu Michihiro , Okada Yukikatsu , Yada Isao , Yudsa Hiroshi , Kusagawa Minoru
Published: July 2010

Abstract: The hemostatic alterations in two adult patients who were supported by left ventricular assist devices (LVADs) because of postcardiotomy heart failure were evaluated. In both patients, fibrinopeptide A and throm–bin–antithrombin III complex increased markedly during the first several days, and thereafter decreased moderately but remained above normal over the entire procedure. Furthermore, fibrinopeptide Bp 15–42 and a2 plas–min inhibitor–plasmin complex were also markedly increased over the entire course of LVAD treatment. These data show that the LVAD system strongly activates both the coagulation and the fibrinolytic system, even when thromboembolic or bleeding complications are not clinically evident. Furthermore, the decrease in physiological coagulation inhibitors, especially protein C, indicates that these factors are activated and consumed during LVAD treatment. Because protein C is important in regulating the coagulation cascade during LVAD treatment, exhaustion of this system might result in thromboembolic complications during LVAD treatment.
Reduced Granulocyte Activation with a Heparin–Coated Device in an In Vitro Model of Cardiopulmonary Bypass
Authors: Videm Vibeke , Nilsson Leif , Venge Per , Svennevig Wan L.
Published: July 2010

Abstract: Granulocyte activation during cardiopulmonary bypass (CPB), resulting in degranulation, may have adverse effects. Fresh whole human blood and priming solution was circulated through oxygenator/tubing sets coated with functional heparin (n = 7) and through un–coated sets (n = 7) in model CPB. Plasma concentrations of the primary granule protein myeloperoxidase (MPO) and the secondary granule protein lactoferrin (LF) were measured in radioimmunoassays, and the neutrophils were counted. After 120 min, seven to nine times baseline concentrations of LF (p < 0.0001) were observed with both devices. Increases of MPO were also significant, but significantly larger (p < 0.01) with the uncoated devices. There was an equivalent reduction in neutrophil numbers in both groups. MPO did not bind to heparin–coated Seph–adex particles in gel chromatography. Thus, the heparin coating most likely prevented the release of potentially harmful primary granule proteins, indicating improved biocompatibility. Adhesion of neutrophils and exocytosis of LF, which may be involved in adhesion, were unaffected.
Concept of a Soft, Compressible Artificial Ventricle Under Evaluation
Authors: Smulders Yvo M. , Tieleman Robert G. , Topaz Stephen R. , Bishop Nolan D. , Yu Long S. , Kolff Willem J.
Published: July 2010

Abstract: This study was designed to compare the relative merits of soft and rigid artificial ventricles. A cascade mock circulation was used to measure cardiac output under different circumstances. The data show that these soft air driven ventricles show a Starling's–like response over a wider range of filling pressures than identical, but rigid, ventricles. Compression of soft ventricles by high intrathoracic pressures was simulated in vitro. Air pressures up to + 20 mm Hg did not seriously affect soft ventricles. Cardiac tamponade was simulated by compressing the ventricle in a closed fluid compartment. Tamponade became severe when volume reduction of the ventricle rose to 60 ml. Hemolysis caused by soft and rigid ventricles was tested in a blood bag set–up and was 48–82% higher in the rigid ventricle, depending on the driving conditions. Possibly, this could be explained by the authors' finding that rigid ventricles showed a 20% higher intraventricular dP/dtmax value than soft ventricles. Soft ventricles were implanted in three calves as a total artificial heart (TAH). Implantation without quick connectors was easy because the surgeon could easily fold and compress the ventricles. No physiological complications of softness were observed. Blood damage in the animals was low (< 5 mg/dl). The authors conclude that soft ventricles show distinct surgical and functional advantages over rigid ventricles.
The New Small Viennese Total Artificial Heart: Experimental and First Clinical Experiences
Authors: Rokitansky A. , Laczkovics A. , Prodinger A. , Trubel W. , Losert U. , Wolner E.
Published: July 2010

Abstract: For bridging to transplantation, a new small total artificial heart (TAH) design has been developed. Function of the two membrane pumps (filling volume left: 87 ml, and right: 75 ml; four mechanical disc valves and screwed connectors) for orthotopic implantation were studied in calf experiments. A calf survival up to 180 days was achieved without problems by pumping with a rate of 117 ± 2.4 beats/min and a cardiac output of 7.4 ± 0.7 L/min. For bridging to transplantation, the New Small Viennese TAH was implanted into a small 45–year–old patient (height 160 cm, weight 75 kg) with end–stage coronary heart disease. The patient deteriorated suddenly [mean aortic pressure: 38 mm Hg; cardiac output (CO): 1.8–2.1 L/min; anuria and multiple organ failure] while waiting for a donor heart. Even though his pericardial space was not enlarged, no fitting problems appeared. By using pumping rates of 104.3 ± 8.7 beats/min, a cardiac output of 5.8 ± 0.63 L/min was achieved (free hemoglobin was 4.1 ± 0.48 mg/dl). Even though blood circulation was reestablished, after a TAH duration of 12 days, multiple organ failure persisted, and TAH bridging had to be stopped. In November 1989, a 50–year–old deteriorating transplant candidate with idiopathic cardiomyopathy was bridged for 6 days. Adjusting the heart rate to 86.5 ± 11.2 beats/min, a CO of 6.84 ± 0.46 L/min was achieved (free hemoglobin was 5.9 ± 1.7 mg/dl). Because of chronic liver dysfunction, the patient developed severe icterus while on the TAH, and it took 2 months after heart transplantation to achieve physiological bilirubin concentrations. The patient recovered fully and remains in excellent condition. Key Words: Bridging–New Small Viennese Total Artificial Heart.
A New Technique for Bridging to Heart Transplantation: Feasibility of Monoventricularization of Bilateral Ventricles with LVAD
Authors: Yozu Ryohei , Haga Yoshiyuki
Published: July 2010

Abstract: Because the prognosis of ventricular septal perforation (VSP) and mitral regurgitation (MR) after acute myocardial infarction (MI) is remarkably poor, heart transplantation would be necessary for many of those patients. A new bridging technique was examined in canine models. The bilateral ventricles communicating through VSP were monoventricularized with mitral valve closure and maintained the pulmonary circulation, which had low vascular resistance. The systemic circulation was maintained by a left ventricular assist device (LVAD) placed between the left atrium and the aorta. VSP and MR were made in eight mongrel dogs (pulmonary to systemic flow ratio = 2.24 ± 0.90). They were then monoventricularized and equipped with LVADs. The hemodynamic state was evaluated (a) in intact hearts, (b) after VSP and MR were made, and (c) after monoventricularization and assisted circulation by LVAD. Cardiac output was (a) 90.60 ± 23.16, (b) 42.23 ± 15.76, and (c) 73.43 ± 15.14 ml/ min/kg (a vs. c: not significant; a vs. b and b vs. c: p < 0.01); mean aortic pressure was (a) 96.75 ± 24.69, (b) 30.25 ± 11.08, and (c) 66.50 ± 18.40 mm Hg (a vs. b: p < 0.01, a vs. c and b vs. c: p < 0.05); central venous pressure was (a) 4.76 ± 1.68, (b) 8.94 ± 2.17, and (c) 10.68 ± 2.43 mmHg(a vs. c: p < 0.01, a vs. b: p < 0.05, and b vs. c: not significant). Mean pulmonary arterial pressure and mean left atrial pressure did not show any significant difference among the three groups. This study supports the feasibility of maintenance of hemodynamics by monoventricularization and LVAD in patients with acute MI complicating VSP and MR.
Artificial Cells: 35 Years
Authors: Chang Thomas Ming Swi
Published: July 2010

Abstract: The first artificial cells were prepared 35 years ago. They contain biologically active materials. They are now being used in medicine and biotechnology. Artificial cells containing adsorbents are already a routine form of treatment in hemoperfusion. This includes treatment for acute poisoning, high blood aluminum and iron, kidney failure, some types of acute liver failure, and other conditions. Artificial cells are being tested for use as red blood cell substitutes. Artificial cells containing cell culture are being tested in animals for the treatment of diabetes, liver failure, and others. Artificial cells containing enzymes are being tested for treatment in hereditary enzyme deficiency diseases and other diseases. Artificial cells containing complex enzyme system can convert wastes like urea and ammonia into useful amino acids. In biotechnology, artificial cells are being used for the production of monoclonal antibodies, interferons, and other biotechnological products. They are also being investigated for use in other applications in biotechnology, chemical engineering, and medicine.
New Approaches for Cardiac Assists: “Back to the Future”
Authors: Kolff Jacob
Published: July 2010

Abstract:The treatment of the modern epidemic of coronary artery disease requires the availability of various cardiac assist devices. A review and future implications of the use of retrograde coronary venous perfusion, the intraaortic balloon, a new ascending aortic pump, variable atrial septal defect, and novel energy sources are discussed.
Artificial Liver Support Based on Artificial Cells with Emphasis on Encapsulated Hepatocytes
Authors: Chang T.M.S.
Published: July 2010

Abstract: Artificial liver support requires more than a detoxification system. We have investigated additional approaches. Microencapsulated hepatocytes increased the survival time of fulminant hepatic failure (FHF) rats. They also lowered the bilirubin in Gunn rats. Xenograft of microencapsulated rat hepatocytes into mice are immunoisolated. The viability of hepatocyte increased from 62 to 100% after 29 days. This is because of accumulation of a hepatic stimulatory factor (> 100,000 D) secreted by the hepatocytes in the artificial cells. A novel two‐step method of cell encapsulation greatly improved immu‐noisolation and biocompatibility. Other metabolic approaches included a multienzyme system for conversion of ammonia to essential amino acid, and removal of bilirubin.