bluuebunny/crossref_metadata_2025 huggingface dataset:
Anatomical Considerations in the Design of a Long‐Term Implantable Human Left Ventricle Assist System
Authors: Fujimoto Luiz K. , Smith William A. , Jacobs Gordon B. , Pazirandeh Pirooz , Kramer John R. , Kiraly Raymond , Golding Leonard , Matsushita Shonosuke , Nosé Yukihiko
Published: November 2008

Abstract: A permanently implantable left ventricle assist system (LVAS) is being developed and is planned to be implanted in the left chest cavity against the chest wall with the electrohydraulic energy converter placed in a resected rib space. The inflow and outflow pump ports are connected to the left ventricle (LV) apex and to the descending aorta, respectively. Three additional major components of this system consist of the transcutaneous energy transmission system (TETS) (Thermedics), the variable volume device (WD), and the internal battery. To finalize the design of this integrated system, key anatomical information was obtained by a special radiographic and angiographic study of 31 adult men with a varying degree of coronary artery disease and myocardial dysfunction. These data were combined with the previous computed tomography study by using a standard vertical reference system. The resultant integrated data, which consist of the three‐dimensional chest model, the LV apex and axis orientation, rib orientation, chest wall thickness, and the descending aorta location, were used to define the design and anatomical locations of the inflow and outflow pump ports, the WD, the pump and energy converter orientation, the TETS, and the internal battery. The most critical component for the design was found to be the inflow system. With regard to the average coronary disease patient, an anatomically practical configuration was demonstrated to exist for the presently proposed LVAS. Design flexibility was allowed for some of the critical components in order to fit the system in a large number of patients regardless of the stage and type of the underlying disease.
A Bedside Micromethod for the Determination of Total Carbon Dioxide in Biological Fluids
Authors: Canaud B. , Araujo A. , Nguyen Q. V. , Flavier J. L. , Mion C.
Published: November 2008

Abstract: The quality control of bicarbonate hemodialysis requires the determination of Tco2, either in blood or in dialysate. The use of the M + D Tco2 kit, a bedside micromethod, gave the authors an economical and reliable solution to this problem.
Electrophoretic Control of Concentration Polarization in Membrane Plasmapheresis
Authors: Profitt Tim W. , Radovich John M.
Published: November 2008

Abstract: Membrane plasmapheresis is the separation of plasma from whole blood using microfiltration membranes. A major operating problem of membrane plasmapheresis is concentration polarization, the buildup of retained cells or solutes on the membrane surface. In this study, an electric field was used to control concentration polarization by transporting the negatively charged cells and solutes away from the membrane surface. Plasma flux and protein concentrations were measured before and after an electric field was applied. The electric field strength ranged from 0.32 to 1.50 V/cm, and the process conditions of blood hematocrit, transmembrane pressure drop, and average shear rate at the membrane surface were kept constant at 30%, 63.5 mm Hg, and 550 s‐1, respectively. The plasma flux increased (10–50%) linearly with the increases in electric field strength, but the plasma protein concentrations in the ultrafiltrate decreased. The electric field dispersed the concentration polarization layer only enough to allow solvent (electrolytes and water) to pass, thus diluting the plasma and decreasing the protein concentration.
A Central Venous (W‐B‐W) Catheter for Multipurpose Vascular Access in Children
Authors: Watson Alan R. , Bahoric Andrej , Wesson David
Published: November 2008

Abstract: A central venous (W‐B‐W) catheter has been developed for vascular access in children of all ages and sizes. The catheter design and implantation technique permit nonsurgical bedside adjustment of catheter position and ease of removal. Multiple possible uses include intravenous fluid administration, blood sampling, central venous pressure monitoring, and plasma exchange therapy in addition to hemodialysis. Twenty‐seven W‐B‐W catheters were placed in 24 patients in a 12‐month period. The catheter provided adequate blood flow for hemodialysis. Seven catheters were removed nonelectively in five patients. One episode of catheter‐associated sepsis occurred after renal transplantation in a patient on immunosuppressive therapy. It is concluded that the W‐B‐W catheter is a relatively safe, multipurpose, pain‐free acute vascular access for children, which may also suffice for chronic hemodialysis.
Determination of Plasma C3a des Arg Levels After Blood Contact with Foreign Surfaces
Authors: Spencer Peter C. , Schmidt Baerhel , Gurland Hans J.
Published: November 2008

Abstract: The products of complement activation, including C3a, C4a, C5a, and their des Arg derivatives, have been used by many investigators as indicators of blood or foreign surface bioincompatibility, e.g., during hemodialysis. One problem encountered is that after extracorporeal circulation over some dialysis membranes very high C3a levels (5,000‐ 10,000 ng/ml) are generated. To the authors' knowledge the only presently available C3a des Arg RIA kit is provided by Upjohn Diagnostics (Kalamazoo, MI, U.S.A.), which covers an assay stan‐ dard range of 20–500 ngiml. Since Upjohn's assay procedure manual does not contain a recommended dilution technique the authors undertook a study to determine thebest method. The diluents tested include physiologic saline, normal plasma, phosphate‐buffered saline‐gelatin, and the Upjohn precipitating agent provided in their kit. The results show that only dilution by normal plasma gave reliable results. The use of the other three diluents resulted in an overestimation of C3a levels. Therefore it is important to know the dilution technique used when comparing the results of membrane C3a generating ability presented by different authors. Furthermore, comparison of different membranes where plasma samples in some cases do not require dilution (e.g., polyacrylonitrile membranes) with those requiring dilution (e.g., regenerated cellulose membranes) will lead to distorted results if an accurate technique is not used.
Totally Implantable Artificial Organ: Cardiac Prosthesis
Authors: Nosé Yukihiko
Published: November 2008

Abstract: This article reviews the current status of completely implantable cardiac prostheses, with an emphasis on those systems presently under development at The Cleveland Clinic Foundation (CCF). Such devices have been one of the final goals of artificial heart research since 1957, when Dr. Kolff initiated these studies in Cleveland. Although earlier plans aimed at using radio‐isotopes as the energy source, more recently, due to public opinion and sociopolitical influences, the shift has been towards exclusive use of electrically activated energy converters. These systems can be roughly broken down into two groups according to the powertrain configuration. In the first group, electric heating coils maintain liquid salts in thermal batteries at temperatures close to 500°C. This thermal energy is then converted (through a Stirling cycle) to mechanical motion of the pusher plate (PP) which in turn acts on the blood. Two such systems (emphasized in this article) are under development here at CCF in joint efforts with Nimbus Corporation and the University of Washington, respectively. In the second group of ventricular assist systems, electric energy is converted directly to PP motion through rotating cams, solenoids, or electrohydraulic transmission systems. At least four American contractors are working at the preclinical stage on this group of devices. One in particular, the CCF‐Nimbus system, consisting of a biolized surface blood pump, an electrohydraulic energy converter, and a compliance chamber to handle the variable volume behind the PP, is described in depth in this discussion.

In terms of future prospects, it is forecasted that by 1988, the completely implantable VAS will be used clinically, and that by 1994, a specially designed total artificial heart (nontethered patient) would be ready for human use.
Arterial Pressure Pulsation During Nonpulsatile Biventricular Bypass Experiments: Possible Idioperipheral Pulsation
Authors: Tsutsui T. , Nosé Y.
Published: November 2008

Abstract: During nonpulsatile biventricular bypass (NPBVB) experiments, regular fluctuations of arterial pressure were observed in all five long‐term animals whose ventricles were fibrillated. Analysis of the characteristics of this fluctuation was performed retrospectively. The pulse pressure of this fluctuation increased gradually after the first 2 weeks. They were 6.7, 7.6, 10.2, and 12.4 mm Hg on the fortieth, sixtieth, eightieth, and ninetieth postoperative day, respectively, in the animal surviving for 99 days. Cycle rate was generally high for the first 40 days, and then decreased to ˜40 cycles/min in calves alive for >90 days. The beat rate of these arterial pressure fluctuations was lower than atrial but similar to respiratory cycle rates. However, no flow fluctuations were observed in conjunction with the arterial pressure oscillations. Therefore, neither atrial contractions nor the mechanical effects of respiration were causing the pressure pulsations. Though further investigations are necessary, it is highly suggestive that this phenomenon was derived from the vasomotor center and can be called “idioperipheral pulsation.” It is conceivable that the NPBVB animals adapted to the nonpulsatile condition by adding active pulsatile components of their own to maintain adequate peripheral circulation.
Short Hemodialysis: Long‐Term Mortality and Morbidity
Authors: Wauters Jean‐Pierre , Bercini‐Pansiot Sylvie , Gilliard Nicolas , Stauffer Jean‐Christophe
Published: November 2008

Abstract: Individualized short hemodialysis treatment schedules, approximately three 3‐h treatments per week, were introduced in a nephrology unit in 1976. In May 1985, 259 patients had been treated, which corresponds to ˜60 new patients per million inhabitants per year. Ages at start of therapy ranged between 17 and 78 years. Patient survival was 91% at 1 year, 76% at 5 years, and 60% at 10 years. The analysis of causes of death did not show an increase in cardiovascular or infectious problems. Hospitalization rate (excluding hospitalization at start of therapy and vascular access problems) was 7 ± 9 days per patient per year (range 2–161). Therefore, it appears that in a largely unselected dialysis population, a schedule of 3‐h hemodialysis three times per week may be safely applied for at least 9 years. The claim that short hemodialysis is associated with increased mortality and morbidity appears to be based on other interfering factors.
Clinical Estimates of Treatment Adequacy
Authors: Teschan Paul E.
Published: November 2008

Abstract: Adequacy of rapid, high‐efficiency therapies (RHET) in patients with end‐stage renal failure involves comparisons with hemodialysis, the primary reference standard. However, the latter's adequacy is also insecurely rendered in descriptive, subjective terms that often embrace outcomes beyond legitimate expectations of the dialysis process. Many measurable abnormalities in renal failure contribute little to patients' clinical illness and respond poorly to dialysis. It is therefore proposed that adequacy for all proposed clinical treatment modalities, including RHET, be based on objective, quantitative measures of what such treatments actually do: control volume and dialyzable solute composition of the body fluids, and suppress the uremic illness. Recognition of the dialysis‐responsive—and also disabling—uremic illness as an encephalopathic, neurobehavioral (NB) disorder logically led to objective documentation of quantitative NB impairments that varied inversely with the amount of hemodialysis and improved following renal transplantation. Similar objective documentations of RHET are needed.
Vascular Prosthesis Standards: A Manufacturer's Viewpoint
Authors: Snyder Roger
Published: November 2008

Abstract: A review of the state of current commercial vascular grafts and the types of tests proposed by the Association for the Advancement of Medical Instrumentation Vascular Prosthesis Draft Standard is presented. The philosophy of the standard and the types of products covered are discussed. Several areas requiring additional development are noted. The status and future of the standard are now up to the general user community.
Efficacy and Safety of Hemoglobin‐Polyethylene Glycol Conjugate (Pyridoxalated Polyethylene Glycol Hemoglobin) as an Oxygen‐Carrying Resuscitation Fluid
Authors: Iwasaki Keiji , Iwashita Yuji , Ikeda Kenro , Uematsu Toshio
Published: November 2008

Abstract: The safety and efficacy of a conjugate of pyridoxalated hemoglobin and polyethylene glycol (pyridoxalated PEG hemoglobin) were evaluated after administration to rats. The LD50 (lethal dose for 50% survival of group) of pyridoxalated polyethylene glycol (PEG) hemoglobin was >200 ml/kg. Any pro‐or anticoagulation activity was not demonstrated in in vitro coagulation tests. One day after 70% exchange‐transfusion with pyridoxalated PEG hemoglobin, slight elevations of the serum glutamic‐oxaloacetic transaminase, serum glutamie‐pyruvic transaminase, and blood urea nitrogen values, which were 101.7 ± 22.6 IU/L, 33.3 ± 7.2 IU/L, and 23.1 ± 1.4 mg/dl, respectively, were observed. However, these values were in the normal range after 3 days. With >90% exchange‐transfusion, all rats exchange‐transfused with pyridoxalated PEG hemoglobin survived for >2 weeks in contrast to the death of all the rats exchangetransfused with stroma‐free hemoglobin or albumin.
Topographic and Dynamic Radioisotopic Investigations of Interactions Between Biomaterials and Blood Components
Authors: Baquey Charles , Basse‐Cathalinat Bernard , Bordenave Laurence , Caix Josseline , Brendel André Jacques , Ducassou Dominique
Published: November 2008

Abstract: Functional investigations using radionuclides to study protein adsorption and platelet adhesion onto biomaterials are described. The authors' novel methods use radiotracers with a dynamic technique. This allows direct observation of the interaction between blood, or simpler biological substances, and artificial materials. Several radiotracers were used in this study, including 111In‐platelets, 123I‐fibrinogen, 123I‐antithrombin HI, and 99mTc‐tagged red blood cells. The detectors employed were a semiconductor diode or gamma‐camera equipped with special collimators. The acquisition and treatment of data were performed with an original device. These methods allowed precise comparisons, especially between platelet adhesion upon different materials in the form of tubes and also protein adsorption and desorption. The results are discussed in terms of materials to be used for work in vivo.
Ethylene Oxide Sensitivity in Hemodialysis Patients
Authors: Pearson F. , Bruszer G. , Lee W. , Sagona M. , Sargent H. , Woods E. , Dolovich J. , Caruana R.
Published: November 2008

Abstract: Sera from 138 patients who had experienced hypersensitivity‐type reactions while on hemodialysis (reactors) were examined retrospectively by the radioal‐lergosorbent test (RAST) for specific IgE antibody to ethylene oxide (ETO). Seventy‐eight hemodialysis patients without a history of reaction were also evaluated as controls. Elevated serum RAST values (> 2.0) were more common in reactors (63%) than in controls (11%, p < 0.001). In a second study, RAST assays were performed using human serum albumin conjugated to ETO (HSA‐ETO) as antigen and also using a concentrate of fluid used to rinse ETO‐sterilized dialyzers (“dialyzer extract”) as antigen. The RAST ratios obtained with HSA‐ETO were similar to those obtained using the dialyzer extract (rank order correlation coefficient = 0.829, p < 0.001). In a third study, RAST inhibition was demonstrated both by HSA‐ETO and dialyzer extract. Our results, extending previously published reports, suggest that hypersensitivity to ETO might play an important role in hemodialysis‐associated hypersensitivity‐type reactions.
Plate, Coil, and Hollow‐Fiber Cuprammonium Cellulose Dialyzers: Discrepancy Between Incidence of Anaphylactic Reactions and Degree of Complement Activation
Authors: Daugirdas John T. , Potempa Leonard D. , Dinh Ngoclan , Gandhi Vasant C. , Ivanovich Peter T. , Ing Todd S.
Published: November 2008

Abstract: During the past 10 years, the incidence of severe anaphylactic reactions during dialysis [type A first‐use syndrome (FUS)] at our center has been much lower when using cuprammonium cellulose plate (CC‐P) dialyzers (0/37,750 dialyses) or coil (CC‐C) dialyzers (0/32,500) than when using cuprammonium cellulose hollow‐fiber (CC‐F) dialyzers (8/21,022 dialyses, p < 0.005 by Chi‐square). To determine if the difference in type A FUS incidence between the three dialyzer types could be explained by differences in complement activation, we compared plasma concentrations of C3a des‐arginine (des arg) in patients undergoing dialysis with these three varieties of dialyzers. Plasma C3a des arg values increased markedly in the dialyzer outflow blood with the three dialyzer configurations. The levels were similar with the dialyzer types when results were corrected for membrane surface area. Also, the degree of leukopenia was not markedly different with the three dialyzer types. Our findings suggest that complement activation per unit surface area is similar during dialysis with plate, coil, and hollow‐fiber cuprammonium cellulose dialyzers. The lack of correlation between the degree of complement activation and the incidence of type A FUS suggests that membrane‐induced complement activation is not of primary importance to type A dialyzer hypersensitivity reactions.
Is Contact Activation of the Coagulation System Involved in the Genesis of the First‐Use Syndrome?
Authors: Vaziri N. D.
Published: November 2008

Abstract: A number of mechanisms have been thought to be involved in the pathogenesis of the first‐use syndrome. These include IgE antibody‐mediated response to ethylene oxide‐related antigens, membrane activation of the alternative complement pathway, activation of tissue mast cells and basophils by materials released from the dialyzer into the circulation, and transfer of bacterial products through high flux dialyzer. However, the possible role of the activation of blood coagulation system and platelets during dialysis has not been considered. The present communication reviews the theoretical basis for a possible connection between dialysis‐induced activation of platelets and coagulation system with the first‐use syndrome. Although the available data concerning the activation of intrinsic coagulation pathway during dialysis are conflicting, there is no controversy as to the occurrence of platelet activation. It is suggested that biochemical events triggered by activation of these systems may in part contribute to the genesis of first‐use syndrome.
Acute Anaphylactoid Reactions During Hemodialysis in France
Authors: Forêt M. , Kuentz F. , Meftahi H. , Milongo R. , Hachache T. , Elsener M. , Dechelette E. , Cordonnier D.
Published: November 2008

Abstract: A retrospective survey of anaphylactoid reactions during dialysis in France was conducted. In 52 of 112 hemodialysis units surveyed 111 patients who had suffered one or more anaphylactoid reactions during dialysis were identified. According to the Hamilton/Adkinson classification, in 31 patients reactions were minor, in 54 patients moderate, and in 26 patients severe. Four patients died of their reactions. A preponderance of reactions (75 and 11%) occurred with cuprammonium cellulose hollow‐fiber and plate dialyzers, respectively. Severe dialyzer reactions were found to occur more frequently after the long (weekend) interdialytic interval. In an in vitro study, six brands of cuprammonium cellulose hollow‐fiber dialyzers were rinsed with water and the eluates analyzed by size exclusion chromatography for contaminant particles. Substantial variation in the amount of extractable material was found between dialyzers of different brands, despite the fact that all dialyzers used membranes from the same manufacturer. Previous data by others has suggested that this extractable material is a derivative of cellulose. Results of our epidemiologic survey in France are similar to those previously reported in the United States and suggest an increased incidence of dialyzer reactions with ethylene oxide‐sterilized cuprammonium cellulose dialyzers. The presence of cellulose‐derived particles in the rinsing fluid of such dialyzers and the possible increased incidence of reactions after the long (weekend) interdialytic interval suggest that allergy to cellulose‐derived particles eluted from cellulosic dialyzers may contribute to dialyzer hypersensitivity reactions.
Hemodiafiltration Using Dialysate as Substitution Fluid
Authors: Canaud B. , Nguyen Q. V. , Argiles A. , Polito C. , Polascheoo H. D. , Mion C.
Published: November 2008

Abstract: To reduce the cost of hemodiafiltration (HDF), a standard hemodialysis machine was modified to permit in‐line production of substitution fluid from bicarbonate dialysate. The authors' present data showing that this procedure was made bacteriologically safe; was simple to use, and offered a cheap approach to perform high‐flux HDF using a hemodifilter of relatively small membrane surface area.
Effect of Acetate Administration on Rats with Chronic Uremia
Authors: Yamamoto Tadashi , Yamakawa Makoto
Published: November 2008

Abstract: To investigate the effect of long‐term acetate administration on uremic and nonuremic rats, the blood lipid level, the incorporation of [14C]acetate into exhaled 14CO2 and into tissue lipids, and morphological changes were studied. Experimental chronic uremia was caused by partial nephrectomy, and sodium acetate of NaCl was given intraperitoneally for ˜12 weeks. Controls were sham‐operated rats given acetate or NaCl. Hyperlipidemia was found in the uremic rats; it was more severe in the rats given acetate. Incorporation of [14C]acetate into 14CO2 was lower in uremic rats given acetate than in other groups, and incorporation into liver lipids was not different in different groups. Small fat droplets had accumulated diffusely in the hepatocytes of nonuremic and uremic rats, but accumulation was more severe in the former. Large fat droplets were found in rats given acetate, mostly in the periphery of liver lobules. Uremic rats given NaCl did not have such changes. The results suggested that chronic acetate administration may contribute to hyperlipidemia in uremic rats and to lipid accumulation in hepatocytes in both uremic and nonuremic rats, causing fatty degeneration of the liver.
Massive Hollow Fiber Clotting: A Distinct Problem in Treatment of Cryoglobulinemia by Membrane Plasmapheresis
Authors: Lai Kar Neng , Cheng Sai Cheong , Vallance‐Owen John
Published: November 2008

Abstract: Two patients with cryoglobulinemia were treated with plasmapheresis in combination with immunosuppressive therapy. One had Waldenstrom's macro‐globulinemia, and the other suffered from systemic lupus erythematosus. Membrane plasmapheresis, using membrane plasma separators, was performed, and the initial plasmapheresis treatments were unsatisfactory because of clotting of hollow fibers by cryoglobulin. The plasma filtration rate and the clearance of immunoglobulins fell rapidly with the clotting of the hollow fibers. This technical difficulty was overcome by prediluting the blood with normal saline before passing it through the membrane plasma separator. The mechanism of preventing clotting of hollow fiber by saline predilution is likely to be the reduction of serum viscosity and the lowering of cryoglobulin concentration. This modification is simple and efficient and enables membrane plasmapheresis to be performed effectively in patients with cryoglobulinemia without complicated and expensive machines.
Role of Hypovolemia in Dialysis‐Induced Hypotension
Authors: Maeda Kenji , Morita Hiroyuki , Shinzato Takahiro , Vega Benjamin Vazquez , Kobayakawa Hiroyuki , Ishihara Toshikazu , Inagaki Hazime , Igarashi Isemi , Kitano Tomoyuki
Published: November 2008

Abstract: Blood volume was measured continuously during hemodialysis using the authors' hematocrit continuous measurement system in an attempt to determine any relationship between dialysis‐induced hypotension with acute onset and blood volume. Hypotension resulted approximately 3 h into dialysis in the present study. This point in time was that at which blood volume was more than 5% above the minimum level during the dialysis treatment, and in some patients it was more than 10% over the minimum level of blood volume. At the time dialysis‐induced hypotension occurred or before, there was no sharp decrease in blood volume nor any change in the plasma refilling rate. This suggested that this hypotension is caused by a sudden breakdown of the blood pressure support mechanism compensating for decreased blood volume.
Changes in Albumin/Platelet Interaction with an Artificial Surface—Due to Antibiotics, Pyridoxal Phosphate, and Lymphocytes
Authors: Chandy Thomas , Sharma Chandra P.
Published: November 2008

Abstract: Protein adsorption and platelet adhesion are two important biological processes arising at the blood prosthetic interface. The effect of certain antibiotics, namely, neomycin, gentamicin, ampicillin, penicillin‐G, and streptomycin to modulate the albumin polycarbonate surface interaction was investigated using 125I albumin from a protein mixture in the presence and absence of isolated calf lymphocytes. This study also demonstrated the changes in platelet‐surface adhesion with these antibiotics. The effect of pyridoxal phosphate to modulate the red blood cell‐mediated platelet‐surface attachment was also attempted. It appears from pyridoxal phosphate studies that pyridoxal 5′‐phosphate (PLP) could modify the surface‐platelet attachment. It also inhibited the fibrinogen‐induced platelet adhesion. It seems, the addition of antibiotics to the polymerprotein system increased the level of surface‐bound albumin variably whereas lym‐phocytes incubated in the medium did not affect the surface‐albumin concentration with time course. These antibiotics also inhibited the surface‐induced platelet adhesion to variable degrees. Our earlier studies have indicated that certain antibiotics or antiplatelet drugs can inhibit the fibrinogen binding to an artificial surface. Therefore, it may be possible that the enhanced albumin‐surface concentration or reduced fibrinogen‐surface binding, in the presence of these antibiotics, may itself be one of the parameter for a reduced platelet‐surface attachment, which may also improve the blood compatibility of the substrate. A better understanding of the mechanism of antibiotics is needed in in vivo conditions to correlate these findings.
Alkalinization of Peritoneal Dialysis Solutions with Sodium Hydroxide or Sodium Bicarbonate
Authors: Daugirdas J. T. , Chaudhry Abdul W. , Ing Ian L.
Published: November 2008

Abstract: Peritoneal dialysis solution containing 1.5% dextrose was titrated with either sodium hydroxide or sodium bicarbonate. The titratable acidity was‐1.5 mmol/L as determined by sodium hydroxide titration. Generation of carbon dioxide on addition of sodium bicarbonate resulted in a titration curve that was shifted downward and to the right compared with the curve for sodium hydroxide addition. The information presented can be used to guide the amount of base to be added when partial or complete neutralization of peritoneal dialysis solution is desired.
Transcutaneous Monitoring of Blood Gas Tensions in Patients on Intermittent Peritoneal Dialysis
Authors: Korzets Zeev , Pomeranz Avishalom , Shachor Yehoshua , Bernheim Jacques
Published: November 2008

Abstract: A relative contraindication to intermittent peritoneal dialysis (IPD) is chronic lung disease. To evaluate whether the instillation of 2 L of fluid into the peritoneal cavity affects respiratory function, five IPD patients were studied in the supine position during the first 4 h of a routine IPD session. Blood gas tensions were monitored transcutaneously throughout the study period. At the onset of dialysis, mean transcutaneous blood oxygen tension (Ptco2) was 70.6 ± 9.1 mm rig. It decreased to 55 ± 9.9 mm Hg (22% change from basal values) during the instillation of dialysate. Upon drainage, Ptco2 returned to baseline. This sequence of events repeated itself on subsequent exchanges, although with decreasing decrements of Ptco2 with each consecutive exchange (decrease to 58.6 ± 7.05, 61 ± 6.5, 63.8 ± 5.2 mm Hg corresponding to 16%, 12.7%, and 9.6%, respectively, during the second to fourth exchanges). Transcutaneous blood carbon dioxide tension, Ptcco2, showed a very mild increase during the study (33 ± 7.1 to 38 ± 6.0 mm Hg). In two patients, the same study protocol was performed during the last 4 h of an IPD session. In these two patients, there was only a 5% variation of Ptco2 from baseline values. These results suggest that an adaptive response to the hypoxemia induced by dialysate instillation rapidly occurs in IPD patients.
Selective Removal of Low‐Density Lipoproteins from Plasma by Polyacrylate‐Coated Fractogel in Vitro and in Experimental Extracorporeal Perfusion
Authors: Thies Karsten , Prigent Sally Anne , Heuck Claus‐Chr.
Published: November 2008

Abstract: Polyacrylate, covalently bound to Fractogel, was tested as a sorbent for lipoproteins from human plasma in a perfusion column. Experiments in vitro indicated complete elimination of low‐density lipoproteins from citrated plasma. No binding of high‐density lipoproteins, fibrinogen, or the complement factors C3 and C4 was observed. Biocompatibility was demonstrated by extracorporeal plasma perfusion in sheep. The results indicate the potential use of polyacrylate‐coated Fractogel for the removal of low‐density lipoproteins from plasma ex vivo.
Prognostic Value of Serum Osmolality Gap in Patients with Multiple Organ Failure Treated with Hemopurification
Authors: Hirasawa Hiroyuki , Odaka Michio , Sugai Takao , Ohtake Yoshio , Inaba Hideo , Tabata Yoichiro , Kobayashi Hirotada , Isono Kaichi
Published: November 2008

Abstract: Serum osmolality gap (OG), the difference between measured and predicted serum osmolality, has been shown to be an excellent parameter to express the amount of conventionally unmeasurable middlemolecular‐weight substances. OG was determined on 29 patients with multiple organ failure (MOF) treated with or without hemopurification. OG significantly increased in proportion to the increase in the number of failed organs and correlated well with APACHE II score. Nonsurvivors showed persistently high OG. OG decreased with plasma exchange and hemoadsorption, but not with hemodialysis, indicating that pathogenic factors can be removed effectively with plasma exchange and hemoadsorption. The patients with OG >20 mOsm/kg‐H20 had very little possibility of survival. These results indicate that OG is an easily determinable, effective parameter to evaluate the severity of the patients' condition, efficacy of hemopurification in removing pathogenic middle‐molecular‐weight substances, and the prognosis of the patient in the treatment of MOF.
The E4T Electric Powered Total Artificial Heart (TAH)
Authors: Smith W. A. , Hete B. F. , Kiraly R. J. , Fujimoto L. K. , Jacobs G. B. , Ishikawa M. , Butler K. , Nosé Y.
Published: November 2008

Abstract: The E4T is a totally implantable total artificial heart (TAH) resulting from many years of research work at the Cleveland Clinic Foundation (CCF) and Nimbus, Inc. It consists of four implanted subsystems: the pumping unit, the variable volume device, the transcutaneous transformer, and the internal battery. The pumping unit consists of two CCF biolized pusher plate pumps, and a Nimbus electrohydraulic energy converter. The control logic is based on a left master, alternating beating scheme. The timing difference between end right eject and end left fill determines the actuator speed adjustment. The pumps free fill, so left‐right flow differences are easily accommodated. A prototype system has been built and begun testing to validate and refine the design details.
Use of a Paracorporeal Pneumatic Ventricular Assist Device for Postoperative Cardiogenic Shock in Two Children with Complex Cardiac Lesions
Authors: Matsuda Hikaru , Taenaka Yoshiyuki , Ohkubo Nobukazu , Ohtani Masakatu , Nishigaki Kyouichi , Ohtake Shigeaki , Miura Takuya , Taenaka Nobuyuki , Takano Hisateru , Hirose Hajime , Kawashima Yasunaru
Published: November 2008

Abstract: Pneumatic ventricular assist device (VAD) was utilized for cardiogenic shock after intracardiac operation in two children with complex cardiac anomalies based with single ventricle. In the first case (a 10‐year‐old), after a modified Fontan operation, VAD was placed between the functional left atrium and ascending aorta, serving as a “artificial single ventricle” with neither pumping chamber nor artificial support in the right side of the heart. The systemic circulation was maintained by keeping relatively high central venous pressure. In another child (a 3‐year‐old) who underwent repair of incompetent atrioventricular valve leaving intracardiac lesions, VAD was placed between the common atrium and ascending aorta, serving as a pump for both pulmonary and systemic circulation with regulation of pulmonary blood flow through an aortopulmonary Gore‐Tex shunt. The circulatory assist with VAD was utilized for 5 and 6 days, respectively. Although weaning from the device was not feasible in both patients because of the pulmonary dysfunction, these experience showed the possible use of VAD for cardiogenic shock after surgery in patients with complex cardiac anomalies.
Removal of Apolipoprotein B from Dog Whole Blood by Ex Vivo Hemoadsorption on Antibody‐Agarose Beads
Authors: Ostlund Richard E.
Published: November 2008

Abstract: Antibody columns for hemoperfusion were prepared by filling 300‐ml polycarbonate canisters with 2% agarose gel beads having attached goat antibodies directed toward apolipoprotein B (apo B), the major apoprotein of low and very low density lipoproteins. Blood was withdrawn from the left external jugular vein of dogs, regionally treated with anticoagulant citrate dextrose solution A, pumped through the antibody column, and returned to the right external jugular vein. Immunoreactive apo B decreased by 81% during passage of blood over the column. Adverse effects were not observed during four weekly hour‐long perfusions with blank columns (agarose beads without antibody attached) followed by four weekly perfusions with antibody columns. The columns were disinfected and stored in 1 M acetic acid and reused weekly in each animal. Recovery of platelets and white blood cells over the columns was 90 and 102%, respectively, with no significant differences between blank columns and antibody‐containing columns. Complement was not consumed during the hemoadsorption procedure. Hemoadsorption on antibody‐agarose columns is a promising potential method for removing toxic molecules and cells from whole blood.
Transplantation of Mucosal Tissue Model Composed of Rabbit Oral Mucosal Cells
Authors: Ebata Koji , Ueda Minoru , Shima Takayoshi , Kaneda Toshio
Published: November 2008

Abstract: :Since skin grafted into the oral cavity does not differentiate into mucosa, its original characteristics remain unchanged. This may cause discomfort to patients treated with such grafted skin, due to the skin's hair follicles and keratinization. This phenomenon is controlled by subepithelial connective tissues, and is thus referred to as the Epithelio‐Mesenchymal Interaction. The grafting of mucosa itself would be preferable, but this procedure is severely limited due to the scarcity of suitable tissue. Accordingly, we have recently prepared artificial mucosa in vitro, using fibroblasts and epithelial cells derived from rabbit oral mucosa and collagen gel, and transplanted it into a donor animal. This paper is the first report of a method using artificial mucosa for the reconstruction of mucosal defects.
Molecular Design of Materials for Cell Separation
Authors: Kataoka Kazunori
Published: November 2008

Abstract: : There has been a strong demand in biomedical sciences to isolate viable cell populations with high yield and purity. An important facet of this work was to develop new polymeric adsorbent for the separation of lymphocyte subpopulations. Based on our strategy of separating cells through their differential ionic affinity toward multiphase‐structured adsorbent with ionically derivatized microdomains, a series of poly(2‐hydroxyethyl methacrylate)/polyamine graft copolymers (HA copolymers) was prepared. HA copolymer columns were found to show specific adsorption affinity toward B lymphocytes, and allows for separation of B and T lymphocytes in high yield and purity with a short operating time. Separation mechanism involved in the resolution of B and T lymphocytes by HA copolymer column is discussed in this paper. Further, photo‐induced desorption of cells from the adsorbent derivatized with photo‐responsive functional group (azobenzene group) was demonstrated to emphasize the feasibility of photo‐regulated chromatography as a novel tool in cell separation technology.
The Physics of Continuous Flow Centrifugal Cell Separation
Authors: Brown Richard I.
Published: November 2008

Abstract: The governing equations defining the separation of blood in continuous flow centrifuges are derived using an empirical model for the viscosity of blood. The effects of fluid shear on the separation process are addressed and further models are developed to permit estimations of shear rate during centrifugation. Simplified predictive equations for species specific separations are developed. Contributions due to shear enhanced diffusion are addressed and found to be negligible at the discontinuous interface between cells and plasma. Experimental results from an investigational centrifuge are presented and compared with theoretical predictions. The role of rouleaux formation in conventional centrifuges is discussed and known centrifugal separation characteristics are explained. The viscosity of blood is related to that for suspensions of rigid particles and an equation for the hydraulic permeability of red blood cell suspensions is derived.
Enzymatic Detoxification Using Lipophilic Hollow‐Fiber Membranes: III. Oxidation Reactions of Sulfides
Authors: Yamamoto T. , Tsikas D. , Brunner G.
Published: November 2008

Abstract: A lipophilic hollow‐fiber membrane preparation that was previously described for glucuronidation and sulfation reactions was used for the enzymatic oxidation of sulfides. Endogenous and exogenous toxins in buffer solution or in serum or blood of intoxicated animals were circulated through the internal lumen of lipophilic hollow fibers. Native liver microsomes of the rabbit were circulated on the outside of the hollow fibers. Lipophilic toxins accumulate in and penetrate through the lipophilic membrane and the toxins are oxidized by the mixed function oxygenase system of liver microsomes. The oxidized products cannot rediffuse to the donor side. The endogenous toxin dimethylsulfide (DMS) was converted on the enzyme side to dimethylsulfoxide (DMSO) and small amounts of dime thy lsulfone, which are hydrophilic and nontoxic substances. Other sulfide compounds, ethylmethylsulfide (EMS) and s‐butylmethylsulfide (BMS), have also been converted to their oxidized forms. The enzymatic clearance of the hollow‐fiber module for DMS in in vivo experiments in the rabbit was found to be 1.30 nmol/ h/mg protein/cm2 hollow‐fiber surface. The transmembranous enzymatic clearance of in vitro oxidation reactions of DMS, EMS, and BMS in buffer solutions (open circuit) were measured, respectively, as 1.63, 3.45, and 5.16 nmol/h/mg protein/cm2 hollow‐fiber surface. This technique allows the enzymatic oxidation of sulfur compounds with liver microsomes in vitro and in vivo without immunological hazards, and it is suited for artificial liver support.
Search for Optimal Frequencies and Amplitudes of Therapeutic Electrical Carotid Sinus Nerve Stimulation by Application of the Evolution Strategy
Authors: Peters Tim K. , Koralewski Hans‐Eberhard , Zerbst Ekkehard
Published: November 2008

Abstract: In humans, electrical, bipolar, bilateral carotid sinus nerve stimulation (CSNS; impulse duration 0.35 ms) was applied, using frequencies between 10 and 110 Hz and voltages between individual thresholds and maximal amplitudes of stimulation. Ten anginal patients and two hypertensive patients were studied at an interval of up to 12 years after implantation of electrodes and a radiofrequency receiver for chronic therapeutic CSNS. In search of combinations of frequency and voltage of CSNS, eliciting largest (“optimal”) depressor responses of blood pressure and heart rate in the individual patient, Rechenberg's evolution strategy was applied. This strategy simulates mutation and selection of biological evolution. In each patient and on each test stimulation, a value of quality was computed from actual heart rate and blood pressure values as a selection criterion for the strategy. Either responses to uninterrupted CSNS were investigated, while stimulation parameters were adjusted every 3 min, according to the strategy, or responses to 3 min of CSNS after a change in stimulation parameters were compared to intercalated 3‐min control periods. In each patient, one or more combined settings of frequency and voltage elicited “optimal” responses. In principle, “optimal” CSNS frequencies ranged between 35 and 105 Hz with large interindividual differences. Due to chronic implantation of electrodes and technical features of radiofrequency transmitted stimulation energy, interindividually different voltages led to an optimal response to CSNS. Also according to the present results, the frequency of CSNS has to be determined individually. It is concluded that the evolution strategy was applied successfully, because voltage and frequency settings leading to “optimal” responses were found within 90‐180 min, whereas intrain‐dividual systematic investigations would not be feasible due to their necessarily very long duration. So far, only short‐term responses have been evaluated. A broader use of the strategy in other applications is encouraged, as for example in pacemaker optimization and especially in functional electrostimulation.
Experience with the Hemasite Vascular Prosthesis
Authors: Viron B. , Lukacs B. , Michel C. , Dosquet P. , Haddoum F. , Thibault P. , Mignon F.
Published: November 2008

Abstract: A 3‐year experience with the no‐needle vascular prosthesis Hemasite, implanted in 10 patients who underwent hemodialysis and have a long history of multiple vascular access failures, is described. During 182 months of follow‐up study, 30 thromboses occurred, while nine of 10 patients did not receive any antiplatelet aggregant treatment. Hemasite was declotted 12 times with a local infusion of urokinase and 12 more times by thrombectomy. A surgical procedure was performed only in the other cases, and the rate of surgical intervention fell from 0.18 interventions per patient per month before Hemasite implantation to 0.027 after implantation.
Optimization of Hemofilters for the Development of Implantable Artificial Kidneys
Authors: Dörp E. , Wüstenberg P. W. , Klinkmann H. , Ivanovich P. , Trekel S.
Published: November 2008

Abstract: The concept of developing an implantable artificial kidney demands, in addition to the regeneration of endogenous filtrate, a small hemofilter with a high filtration rate (1‐4). Conventional capillary filters are limited in their capacity to yield adequate filtrate, even if the number of capillaries is increased (5‐7). To improve filter design so as to modify flow conditions for filtration rate augmentation, it is necessary to consider such factors as blood flow through a single capillary, wall shear rate, and transmembrane pressure (ptm) in in vivo applications, where such biological considerations as blood pressure, blood flow, and flow characteristics of blood are important. These requirements lead to a completely new filter type, the “curl filter,“ characterized by a large effective filtration surface in a relatively small number of hollow fibers in which optimal flow conditions prevail.
Gas Supply Across Membranes in Bioreactors for Hepatocyte Culture
Authors: Gerlac J. , Klöppel K. , Stoll P. , Vienken J. , Müller C.
Published: November 2008

Abstract: The conditions required for hepatocyte cultures is a main topic in the development of bioreactors for hybrid liver support systems. The detoxification of ammonia and the synthesis of urea due to primary isolated hepatocytes was measured in order to compare two different models of gas supply in bioreactors: (a) indirect medium oxygenation and (b) direct membrane‐contact oxygenation of the hepatocytes using polypropylene membranes. Increasing oxygen pressure promoted cell function. At day 6 of culture, urea synthesis was 0.8 ± 0.3 raM in 21% of 02 cultures and 1.5 ± 0.1 mM in oxygenated cultures. Alkalosis due to C02 loss decreased ammonia metabolism. The direct membrane‐contact oxygenation resulted in enhanced cell metabolism in comparison to medium oxygenation: urea synthesis at day six was 1.42 ± 0.2 mM in 21% O2 cultures. Polypropylene oxygenation membranes proved to be sufficient for hepatocyte adhesion. Two functions can be integrated in one element in liver support systems using the investigated polypropylene membrane and the direct membrane‐contact oxygenation: oxygenation with physiological oxygen pressure in bioreactors due to gas supply across the membrane and adhesion of hepatocytes in bioreactors on the membrane.
Endothelial Cell Seeding of Small Diameter Vascular Grafts
Authors: James N. L. , Schindhelm K. , Slowiaczek P. , Milthorpe B. K. , Dudman N. P. B. , Johnson G. , Steele J. G.
Published: November 2008

Abstract: This study examines, under flow conditions, the adhesion of endothelial cells to 3 mm diameter fi‐bronectin (Fn)‐coated expanded polytetrafluoroethylene (PTFE) vascular grafts. Cultured ovine carotid artery endothelial cells were labelled with 35S‐methionine. The grafts were seeded with endothelial cells (1.5 times 106/ml) by rolling for 1 h at 37d̀C and then either cultured to confluence for 48 h or flow tested immediately. Cell attachment to grafts (n = 5) was evaluated in an in vitro flow circuit, using flows of up to 330 ml/min. Ex vivo studies (n = 5 grafts) were conducted without anticoagulant using autologous cells in a sheep model. Grafts were inserted into an externalized carotid‐jugular shunt and exposed to blood flows of ˜150 ml/min for 3 h. One hour seeded and 48 h cultured grafts demonstrated <95% cell retention following in vitro flow studies. Ex vivo studies of 48 h cultured grafts gave endothelial cell retention of 81% with no sign of thrombogenicity. Furthermore, a preliminary 24 h ex vivo study has shown <95% retention. This study demonstrates the firm attachment of seeded endothelial cells to Fn‐coated PTFE grafts in the sheep model.
Hand‐Made Valved Conduit with High‐Porosity Knitted Graft and Glutaraldehyde‐Treated Autologous Pericardial Trileaflet Valve
Authors: Matsuda Hikaru , Kawata Hiroaki , Miyamoto Katsuhiko , Tokuan Yosihisa , Kasai Yumiko , Kobayashi Jyunjiro , Matsuki Osamu , Kawashima Yasunaru
Published: November 2008

Abstract: In 10 patients with various congenital heart defects requiring reconstruction of right ventricle to pulmonary artery continuity, a new hand‐made valved conduit was introduced. To avoid late stenosis with peel formation of the graft, high‐porosity Golaski knitted graft was chosen. The graft was sealed by fibrin glue, and autologous pericardium was treated with glutaraldehyde and used to construct a trileaflet valve inside the graft. This hand‐made graft was pliable with good conformability. The valve function was found good in the intermediate follow‐up in 8 patients. This composite valved conduit may be a good alternative to the xenograft valved conduit when allograft conduit is not available.