bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum and Intracellular Detection of Cytokines in Patients Undergoing Chronic Hemodialysis
Authors: Roccatello Dario , Formica Marco , Cavalli Guido , Quattrocchio Giacomo , Aimo Giuseppe , Polloni Renato , Amprimo Maria C. , Moho Andrea , Martha Guido , Isidoro Ciro , Mazengo Maurizia , Coppo Rosanna , Sena Luigi M. , Piccoli Giuseppe
Published: July 2010

Abstract: Tumor necrosis factor (TNF) was detected, before and after dialysis, in sera from 69 patients and, at various times during dialysis, in 28 patients carefully selected for the absence of intercurrent illness. Blood samples were also sequentially collected for separation of monocytes, and cells were sonicated to detect intracellular TNF. Compared with serum levels obtained from 41 healthy subjects, basal TNF values of the unselected group of 69 patients were significantly higher (p < 0.01), independent of the dialyzer membrane. A significant increase in TNF levels by the end of dialysis was found only with Cuprophan (p < 0.01). In the selected group of 28 patients, no significant changes in TNF values were observed in sequential samples. However, a significant increase of intramonocyte TNF levels was found in Cuprophan patients (p < 0.025). Soluble interleukin‐2 receptor (IL‐2R) levels, measured in parallel in sera from unselected and selected patients, were found to be very much higher than healthy controls without significant changes during the dialysis procedure. While the diverse profiles of TNF obtained from differently selected patients suggest that mechanisms other than membrane biocompatibility play a role in the appearance of these low cytokine levels, the possible nature of uremic toxin for soluble IL‐2R can be envisaged by detection in dialysis patients.
Antithrombogenicity of Polyacrylonitrile‐Polyethyleneoxide Hollow Fiber Membrane Developed for Designing an Antithrombogenic Continuous Ultrafiltration System
Authors: Arakawa Masaaki , Aoike Ikuo , Sizuki Yasushi , Gejyo Fumitake , Terada RYOZO , Sugaya Hiroyuki , Takeyama Takayuki , Kunitomo Tetsunosuke
Published: July 2010

Abstract: To develop a continuous arteriovenous hemo‐filtration (CAVH) system, which does not need systemic anticoagulation, for patients of acute renal failure having bleeding tendencies, a totally antithrombogenic continuous ultrafiltration system (ACUS) was designed, which consists of an antithrombogenic polyacrylonitrile‐poly‐ethyleneoxide (PAN‐PEO) hollow fiber membrane and ionically heparin‐bound catheter, tubing, and module header. Antithrombogenicity of PAN‐PEO membrane, which occupies more than 90% of total inner surface area of ACUS, was considered to be due to highly concentrated PEO near the inner surfaceaof the membrane and the finely dispersed (less than 500 Å) microstructure of the inner surface. ACUS was applied to 24 patients without systemic anticoagulation, and one filter worked for an average of 32 h without deteriorating their bleeding tendencies. Any significant changes in major parameters of biocompat‐ibility during those treatments were not observed. More than 200 ml/h of ultrafiltrate was obtained even under very low mean blood pressure, less than 70 mm Hg. Based upon these results, ACUS was concluded to be suitable for mild and sustained treatment to control fluid and electrolyte balance in patients of acute renal failure with bleeding complications.
Pregnancies Following Implantation of an Artificial Fallopian Tube in Rabbits
Authors: Grimaldi Giuseppe , Zobell Richard L. , Scott James R. , Urry Ronald L.
Published: July 2010

Abstract: The first cases of pregnancies obtained in vivo in animals after implantation of a Teflon artificial fallopian tube model are presented. The Teflon prosthesis was implanted into the uterine cornua of rabbits and fixed subcutaneously in the abdominal wall. Five to eight blas‐tocysts obtained from donor rabbits were transferred through the tubing into each recipient animal's uterus 2 to 14 days after placement of the device. On posttransfer day 10, normally developed pregnancies were visible and confirmed histologically in 4 of 7 animals.M
New Sequential Synchronized Driving System of Intraaortic Balloon Pumping and Left Ventricular Assist Device: Influence on Endocardial Viability Ratio and Renal Blood Flow in Their Combination
Authors: Nagasuku Fujio , Husegawa Takamitsu , Shiono Motomi , Orime Yukihiko , Sezai Yukiyasu
Published: July 2010

Abstract: Intraaortic balloon pumping (IABP) and left ventricular assist devices (LVAD) have shown remarkable progress individually, but how to combine them is still unknown. A new sequential synchronized driving system was developed to control concomitant use of IABP and LVAD, and then its hemodynamic effectiveness was evaluated in swine, especially on endocardial viability ratio (EVR) and renal blood flow. This system (pulsatile bypass pump‐delay divide system, PBP‐DDS) made it possible to change the driving phase of IABP and LVAD easily. In 12 swine, IABP and LVAD were set up, and these devices were driven in the following 5 modes with the PBP‐DDS: mode I, IABP alone; mode II, LVAD alone; mode III, IABP + LVAD (same timing); mode IV, IABP (early diastole) + LVAD (late diastole); and mode V, LVAD (early diastole) + IABP (late diastole). EVR was increased more markedly by combined use of both IABP and LVAD (modes III, IV, and V) than by individual drive, but there was no significant difference among these modes. On the other hand, renal blood flow was decreased so dramatically by the same timing optimal counterpulsa‐tion method of mode III that it was thought to be harmful for renal function. But, the delay divide combination method of modes IV and V resulted in no change in the renal circulation. So, it was concluded that this delay divide combination mode appeared to be a more promising support to both failed heart and renal circulation.
Artificial Liver
Authors: Konstantin Peter , Chang Jorge , Otto Veit , Brunner Gorig
Published: July 2010

Abstract: Without transplantation, approximately 90% of patients with fulminant hepatic failure die. If patients receive a liver transplant, there is often a lag between the need for and the availability of a donor liver. Therefore, there is a definite need for a liver support system to support the patient's own liver function in fulminant hepatic failure and while awaiting transplantation. We have developed an artificial liver system that not only eliminates lipophilic toxins such as phenols, fatty acids, and mercaptans, but also hydrophilic ones such as ammonia. This artificial liver system consists of a monitor, an extracorporeal blood circuit that uses a hydrophilic polysulfone high‐flux dialyzer to remove water‐soluble metabolites, and a novel hydrophilic liquid membrane filter to remove lipophilic toxins. In more than 100 in vitro experiments using porcine (5 I) blood, the system was evaluated for its ability to remove toxins that are normally increased in hepatic failure. We found that phenol, cresol, and short‐ and medium‐chain fatty acids can be almost completely eliminated from the blood within 5 h. In animal experiments using pigs, we also found no significant changes of blood gases, liver parameters, electrolytes, and blood cell counts.
The Pressure‐Induced Calcium Deposition on Crosslinked Polyurethanes
Authors: Shunmugakumar N. , Jayabalan M.
Published: July 2010

Abstract: The pressure‐induced calcium deposition in crosslinked polyurethane was studied. Two polyurethane systems, IPDI‐PTMG/PPG‐TMP and SMDI‐PTMG/PPG‐TMP were subjected to calcification under induced pressure. Calcium deposition in IPDI polymers was linear with the increase of soft segment (PTMC) content whereas in SMDI polymers the reverse trend was observed. Decreased phase mixing and hydrophilicity in the polymer (SMDI based) having increased soft segment content was attributed to the decreased calcification. The enhanced amount of calcium deposition under pressure indicates the possible influence of pressure on calcification.
Improved Postfixation Treatment of Glutaraldehyde Fixed Porcine Aortic Valves by Monosodium Glutamate
Authors: Liao Kangxiong , Seifter Eli , Hoffman Darryl , Yellin Edward L. , Frater Robert W.M.
Published: July 2010

Abstract: The use of bioprosthetic valves remains limited due to poor long‐term durability primarily because of tissue calcification‐associated degeneration. Release of locally cytotoxic residual aldehyde after glutaraldehyde fixation is one of the major causes of this degeneration. In this study, monosodium glutamate was used as postfixation treatment to bind residual aldehyde in order to block its toxic effects. Thirty‐six pieces of fresh porcine aortic valves were fixed by 0.625% glutaraldehyde for 14 days, and then 18 of them were treated with 1% monosodium glutamate for another 3 days before they were implanted subcutaneously into the backs of two groups of rats (n = 9 in each group) for 45 and 90 days, respectively. Retrieved specimens were examined grossly, and calcium analysis and measurements of tissue collagen and water content were carried out. The results showed that, compared with glutaraldehyde fixed specimens, monosodium glutamate postfixation treated specimens had less calcification (calcium 104.93 + 50.94 versus 141.58 ± 58.10 at 45 days and 103.07 ± 76.48 versus 199.33 ± 53.44 at 90 days, μg/mg dry weight, p < 0.01), higher collagen content (hydroxy‐prolines.50 ± 1.29 versus 3.58 ± 1.48 at 45 days and 5.64 ± 0.87 versus 4.25 ± 0.65 at 90 days, μg/mg wet weight, p< 0.01), and higher water content (68.00 ± 6.95% versus 61.33 ± 8.83% at 90 days, p < 0.05) (mean ± SD, paired t test). We conclude that monosodium glutamate couples with residual aldehyde, which significantly reduces calcification of glutaraldehyde fixed porcine aortic valves while preserving a higher tissue collagen and water content after implantation. The preserved tissue collagen and water content of the implants is closer to that of unimplanted native valves.
Critical Anatomic Dimensions for Intrathoracic Circulatory Assist Devices
Authors: Mussivand Tofy , Masters Roy G. , Hendry Paul J. , Rajagopalan Kesava , Walley Virginia M. , Nahon Daniel , Hicks Andrew , Keon Wilbert J.
Published: July 2010

Abstract: The design of totally implantable circulatory support devices must account for the anatomical constraints of the body cavity. To aid development of an implantable electrohydraulic ventricular assist device (EVAD), thoracic anatomical measurements and fit trials were performed. Various dimensions of the thoracic cavity were measured in 19 preserved and fresh cadavers. The mean left ventricle apex to chest wall distance was 2.7 ± 0.2 cm. The mean sagittal radius of curvature at the fifth rib was 11.1 ± 0.4 cm, and the transverse radius at the fifth rib was 9.4 ± 0.3 cm. The mean sternal length was 18.9 ± 1.2 cm. Using these measurements a model measuring 17.5 ± 10.5 ± 3.8 cm was designed, This model was placed in the chest of 11 patients undergoing open heart surgery. In one patient there was significant lung compression and in another hypotension suggesting great vessel compression. Finally, 1 of 11 patients had a short sternum and a small thorax, and the device did not fit. In conclusion, thoracic measurements may be used in the design of circulatory support devices. The model fit adequately in 73% of patient trials.
Hemodynamic Evaluation of a New Left Ventricular Assist Device: An Integrated Cardioassist Catheter as a Pulsatile Left Ventricle‐Femoral Artery Bypass
Authors: Ide Hirofumi , Yamaguchi Atsushi , Ino Takashi , Matsumoto Hiroshi , Fujimasa Iwao
Published: July 2010

Abstract: We developed a new left ventricular (LV) assist catheter (transaortic valve from LV to femoral artery) that is implemented percutaneously and exerted as a synchronous pulsatile partial LV flow support with conventional intraaortic balloon pump (IABP) driving system and centrifugal pump system. We investigated whether this pulsatile LV‐aorta bypass is superior to the IABP from a hemodynamic viewpoint. Ten dogs with profound heart failure were placed on this device. and hemodynamic measurements were performed under on‐off study of this system. The results revealed a significant increase of mean aortic pressure, total cardiac output, and myocardial blood flow, and a significant reduction of left atrial (LA) pressure and LV afterload estimated by diastolic pressure‐time indexitension‐time index (DPTI/TTI) measurement compared with baseline values and also with IABP exertion alone. These findings suggest that this system is of clinical value for supporting an impaired LV that is intractable under IABP counterpulsation.
C3a and C5a Anaphylatoxins Bind to Heparin‐Based Sorbent in Low Density Lipoprotein Apheresis: In Vitro and In Vivo Investigations
Authors: Sinitsyn Vladimir V. , Bokchubaev Earnest T. , Mamontova Anna G. , Ovtrakht Nataly V. , Nasonov Eugeny L. , Konovalov Genady A. , Kukharchuk Valery V.
Published: July 2010

Abstract: Plasmasorption on a heparin‐based sorbent was performed in vitro. It demonstrated affinity of the C3a and C5a anaphylatoxins for the sorbent: C3a was removed almost completely (97%), and the C5a concentration decreased on average by 55%. The plasma level of C3a and C5a complement components was also monitored during the procedure of clinical extracorporeal low density lipoprotein (LDL) apheresis on the sorbent in patients with familial hypercholesterolemia. A two‐ to threefold increase in C3a (up to 1,500 ng/ml) was observed after plasma separation by the IBM 2997 cell sorter. Subsequent processing of the plasma through the column led to the low level of C3a detected (less than 50 ng/ml), demonstrating significant uptake of C3a by the sorbent column. The removed C3a was found in the eluate obtained after regeneration of the sorbent with 2 M NaCl solution. No significant increase in C5a was found during the procedure. Nevertheless, some C5a was detected in the eluate from the sorbent. The content of C3a and C5a in patients' blood after the treatment was approximately the same as it was initially, 200–500 ng/ml for C3a and less than 10 ngiml for C5a. The removal of C3a and C5a anaphylatoxins by heparin‐based sorbent should be regarded as an advantage of this type of plasmasorbent.
Development of a Flow‐Transformed Pulsatile Total Artificial Heart for Total Implantation
Authors: Imachi Kou , Chinzei Tsuneo , Abe Yuusuke , Mabmchi Kunihiko , Imanishi Kaoru , Yonezawa Takumi , Suzuki Akira , Isoyama Takashi , Atsumi Kazuhiko , Fujimasa Iwao
Published: July 2010

Abstract: To realize a totally implantable total artificial heart (TAH), a new pulsatile TAH, the flow‐transformed pulsatile TAH (FTPTAH), was developed. The system was composed of a single centrifugal pump (CFP) and two three‐way valves. One port of each three‐way valve was connected to the inlet and outlet of a CFP. The other two ports of each valve were connected to the right and left atrium, and the pulmonary artery and aorta. The CFP can perfuse the pulmonary and systemic circulation alternately with pulsatile flow by switching the two three‐way valves. A prototype and the secondary model in which the solenoid valves and a spool valve were included, respectively, were connected to a mock circulatory unit with the results that a pulsatile TAH with physiological flow wave form could be obtained from a single CFP, about 5 Llmin of pulsatile output could be obtained alternately on the right and left side by switching the solenoid valves or a spool valve, and flow balance between the right and left could be easily controlled by the switching duration. The system is feasible for a totally implantable TAH because it does not need a compliance chamber and can be miniaturized.
A Heparin‐Coated Circuit Reduces Complement Activation and the Release of Leukocyte Inflammatory Mediators During Extracorporeal Circulation in a Rabbit
Authors: Plötz Frans B. , van Oeveren Willem , Hultquist Karl A. , Miller Cathie , Bartlett Robert H. , Wildevuur Charles R.H.
Published: July 2010

Abstract: Heparin coating modifies complement activation during extracorporeal circulation much more effcclively than systemically administered heparin. This rabbit study was undertaken to address possible mechanisms responsible for this difference. We evaluated the effect of heparin coating on complement activation and subsequently the release of leukocyte inflammatory mediators during extracorporeal circulation through a simplified circuit. We found in the heparin‐coated group a significantly reduced complement hemolytic activity (CH50), remaining higher leukocyte numbers, significantly decreased release of β‐glucuronidase, and most strikingly a complete prevention of tumor necrosis factor (TNF) formation. The significantly reduced CH50 activity in the heparin‐coated groups indicates the reduction of one or more native classical complement products. This could be explained by the absorption of complement components by the circuit, which results in reduced activity of the complement cascade. We conclude therefore that heparin coating reduces complement activation and consequently reduces the release of leukocyte inflammatory mediators.
Development of Totally Implantable Electromechanical Artificial Heart Systems: Baylor Ventricular Assist System
Authors: Sasaki Tatsuya , Takatani Setsuo , Shiono Motomi , Sakuma Ichiro , Glueck Julia , Noon George P. , Nosé Yukihiko , DeBakey Michael E.
Published: July 2010

Abstract: An implantable electromechanical ventricular assist system (VAS) intended for permanent use has been developed. It consists of a conically shaped pumping chamber, a polyolefin (Hexsyn) rubber diaphragm attached to a conically shaped pusher‐plate, and a compact roller‐screw actuator. Design stroke volume is 63 ml. The device weighs 620 g, and has a total volume of 348 mi. The pump can provide 8 Limin flow against 120 mm Hg afterload with a preload of 10 mm Hg. The inner surfaces are biolized by dry gelatin coating, with inflow and outflow ports accommodating tissue valves. Three subacute in vivo validation studies have been conducted in calves up to two weeks. The entire system functioned satisfactorily in both the filliempty and the fixed‐rate modes. There was no thromboembolic complication without anticoagulation. The pump showed reasonable anatomical fit inside the left thorax. This VAS is compact, efficient, quiet, and easy to control.
Short Time Treatment with High‐Efficiency Paired Filtration Dialysis for Chronic Renal Failure
Authors: Marangoni Roberto , Savino Renato , Colombo Roberto , Cimino Roberto , Civardi Fernando
Published: July 2010

Abstract: With the aim of treating with short sessions even chronic uremic patients with cardiovascular instability, we have developed our previous findings about paired filtration dialysis (hemofiltration‐hemodialysis in series) by a method we call high‐efficiency paired filtration dialysis (HEPFD). We have treated with this method for 6 months 6 chronic anuric uremic patients previously treated for 6 months with hemofiltration (HF) because of their cardiovascular instability. By comparison with HF, HEPFD shows much higher clearances of small molecules with consequent significant decrease of their predialytic values, improvement of Kt/V value, lower β2‐microglobulin clearance (its predialytic value remains unchanged), and the same tolerability. HEPFD allows short, efficient, and well‐tolerated treatments even in patients with cardiovascular instability.
Adsorption of Nafamostat Mesilate by Hemodialysis Membranes
Authors: Inagaki Oshi , Nishian Yoshihiko , Iwaki Ryotaro , Nakagawa Kiyohiko , Takamitsu Yoshihiro , Fujita Yosikazu
Published: July 2010

Abstract: The adsorption of the anticoagulant nafamostat mesilate (FUT‐175) by five different hemodialysis membranes was studied in vivo and in vitro. In vivo, FUT‐175 was adsorbed strongly by a polyacrylonitrile (AN69) membrane and slightly by another polyacrylonitrile (J‐PAN) membrane but not by Cuprophan (CU), hemophan (HE), or polymethylmethacrylate (PMMA) membranes during hemodialysis performed in 4 patients in whom FUT‐175 was used as an anticoagulant. Only during hemodialysis using the AN69 membrane did FUT‐175 not induce a significant prolongation of celite‐activated coagulation time. In vitro studies showed that FUT‐175 was adsorbed by the AN69, J‐PAN, and PMMA membranes but not by the CU and HE membranes. Methylene blue, a dye that possesses a cationic portion in its chemical structure, stained AN69, J‐PAN, and PMMA membranes. Since FUT‐175 also possesses a cationic portion, we conclude that FUT‐175 is adsorbed by negatively charged membranes via an ionic bond and is unsuited for use as an anticoagulant in hemodialysis using an AN69 membrane because of that membrane's marked capacity to adsorb FUT‐175.
Development of an Atraumatic Small Centrifugal Pump for Second‐Generation Cardiopulmonary Bypass
Authors: Jikuya Tomoaki , Sasaki Tatsuya , Aizawa Takeshi , Shiono Motomi , Glueck Julia A. , Smith Charles P. , Feldman Louis , Sakuma Ichiro , Sekela Mike E. , Noda Toshiaki , Takatani Setsuo , Noon George P. , Nosé Yukihiko , DeBakey Michael E.
Published: July 2010

Abstract: A small and light direct‐drive centrifugal pump has been developed for cardiopulmonary bypass. In the development process, blood compatibility studies including a hemolysis study, an in vitro fluid dynamic performance study, and in vivo durability and feasibility studies were performed. The centrifugal pump with a 50 mm diameter impeller resulted in almost the same index of hemolysis value as did a Bio‐Medicus centrifugal pump. Heat dissipation from the motor was prevented by using a flexible drive cable. Forty‐eight‐hour sealing durability around the driving axis was accomplished by using a fluoro‐rubber V‐ring that connected to the hard chrome‐plated stainless steel. In vitro and in vivo performances of the pump were satisfactory. Thrombus formation behind the impeller was prevented by using a holed impeller that generated blood flow from the back to the surface of the impeller. Elimination of air during priming procedures was also easier with this modification. This centrifugal pump has one‐quarter of the priming volume, size, and weight of magnetically coupled centrifugal pump systems.
Versatile One‐Piece Total Artificial Heart for Bridge to Transplantation or Permanent Heart Replacement
Authors: Orime Yukihiko , Takatani Setsuo , Shiono Motomi , Sasaki Tatsuya , Minato Naoki , Ohara Yasuhisa , Swenson Charles A. , Noon George P. , Nosé Yukihiko , DeBakey Michael E.
Published: July 2010

Abstract: A versatile, one‐piece total artificial heart (TAH) system that can be driven by either an electromechanical acutator (EM‐TAH) or a pneumatic source (P‐TAH) has been developed. The common units for both TAHs are the conically shaped left and right pusher‐plate‐type pumps (63 ml SV) that sandwich a thin centerpiece (18 mm) having a respective actuator. The EM actuator, mounted in the middle of the centerpiece, consists of a direct‐current brushless motor and a roller screw while the pneumatic actuator consists of a low‐pressure air source. The outer diameter of the pumping unit is 97 mm with its central thickness being 82 mm; overall volume is 510 cc. The TAH is operated in the left master alternative ejection mode with the left pump fill signal. High‐flex‐life Hexsyn rubber is used as the diaphragm, and the blood‐contacting surface is coated with dry gelatin. The TAH can provide 3–8 Limin flow with a preload of 1–10 mm Hg against 100 mm Hg afterload. Anatomical fit of the pumping unit has been demonstrated in the pericardial space of 26 heart transplant recipients with average body weight of 78 kg. To date, 2 P‐TAH and 4 EM‐TAH (1 week) implantations were performed in 80–100 kg calves demonstrating excellent anatomical fit, controllability, and biocompatibility. This versatile TAH is suitable for a bridge to transplantation or permanent heart replacement.
Dependence of Baroreceptor‐Mediated Sympathetic Outflow on Biventricular Assist Device Driving Frequency
Authors: Yambe Tomoyuki , Nitta Shin‐ichi , Katahira Yoshiaki , Sonobe Taroh , Naganuma Shigeru , Kakinuma Yoshito , Akiho Hiroshi , Izutsu Kenji , Kikuchi Yuhichi , Tanaka Motonao , Miura Makoto , Sato Naoshi , Mohri Hitoshi , Yoshizawa Makoto , Izumi Kyou‐ichiroh , Takeda Hiroshi
Published: July 2010

Abstract: To investigate the drive condition of the artificial heart from a neurophysiological point of view, the dynamic transduction characteristics of the baroreflex system were analyzed by means of sympathetic neurograms. Two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses (BVBs) in adult mongrel dogs to compare the natural heart circulation and prosthetic circulation. After BVB pumping was initiated, the natural heart was electrically fibrillated. Renal sympathetic nerve activity (RSNA) was recorded to analyze sympathetic outflow. Coherence function between the arterial pressure and RSNA was calculated to evaluate the linearity of the baroreflex system. The largest peak coherency was observed when BVB was driven at the frequency of natural heart beat prior to electrical fibrillation, which suggests that the baroreflex system shows the largest linearity at this frequency. These results suggest the possibility that the natural heart heat frequency is the setting frequency at which the baroreflex system transfers the hemodynamic rhythm to the sympathetic outflow.
Analysis of Phosphate Kinetics in Hemofiltration and Hemodiafiltration: Formulation of an Efficiency Index
Authors: Maurizio Nordio , Giannino De Cecco , Fabio Mirandoli , Giovanni Cocco , Cristina Lombini , Laura Guarda , Pietro Marchini , Santino Lorenzi , Silvio Giove , Carla Nardelli
Published: July 2010

Abstract: The kinetics of phosphate (P) during a treatment of hemofiltration or hemodiafiltration follows a simple exponential law, and P in 90 min reaches a stationary level that remains constant until the end of the treatment. The theoretical compartmental model cannot be estimated by a dialytic treatment, but a simpler diffusive model may be considered. Once the stationary level is reached, the net flux of P from the inaccessible compartments to the accessible compartment may be estimated via the parameters obtained in the exponential model. Hemodiafiltration seems more efficient than hemofiltration in determining P clearance. Thus an efficiency index that accounts for the period in which P is eliminated from the accessible compartment has been formulated.
Experimental Results Using Nafamostat Mesilate as Anticoagulant During Extracorporeal Lung Assist for 24 Hours in Dogs
Authors: Okamoto Taisuke , Chung Young Kyun , Choi Hyun , Terasaki Hidenori , Morioka Tohru
Published: July 2010

Abstract: We report on the experimental application of nafamostat mesilate (NM, 6‐amidino‐2‐naphthyl p‐guanidinobenzoate dimethanesulfonate, FUT®), a new anticoagulant, to extracorporeal lung assist (ECLA) with an artificial membrane lung. Venovenous ECLA, from the jugular vein to the femoral vein, was performed with a hollow‐fiber membrane lung at a blood flow rate of approximate 82 ml kg‐1 min‐1 for 24 h in 7 dogs under anesthesia and hypoventilation. Heparin (10 U ml‐1 in a priming lactated Ringer solution of 140 ml, and 200 U kg‐1) was administered before blood access cannulation. After start of ECLA, however, no heparin was used, and nafamostat mesilate was continuously infused into the drainage line of the bypass circuit to control activated coagulation time (ACT) at about 150 to 200s. To maintain the prolonged ACT, 8:0 ± 1.7 mg kg‐1 h‐1 of NM was required. Arterial blood pressure and pulse rate decreased significantly. Though fibrin monomer test revealed hypercoagulability after 6 h of ECLA, platelet counts did not significantly decrease. Total blood loss remained less than 40 g. The artificial membrane lung sustained a good gas exchange and low flow resistance throughout ECLA. Macroscopic examination revealed small spotty thrombi in the artificial lung but no major pathologic changes of the visceral organs in the all dogs at autopsy. High‐dose NM administration could control blood coagulation and decrease blood loss during ECLA for 24 h without deterioration of the artificial lung and systemic complication other than mild hypotension and bradycardia.
Mechanical Circulatory Support for Postcardiotomy Ventricular Failure: The Heart Institute of Japan Experience 1984–1992
Authors: Kitamura Masaya , Hirota Jun , Niinami Hiroshi , Nishida Hiroshi , Endo Masahiro , Hashimoto Akimasa , Koyanagi Hitoshi
Published: July 2010

Abstract: In the last 9 years, 30 patients received assisted circulation or a ventricular assist device after open‐heart operations at the Heart Institute of Japan. After cardiovascular surgery, 9 of those patients underwent venoarterial bypass, 10 had biventricular bypass, 7 had left ventricular bypass, and the remaining 4 received a left ventricular assist device. Of the first 15 patients, only 3 (20%) were discharged from the hospital. In contrast, 7 (46.7%) of the last 15 patients were discharged without major complications. With respect to complications, bleeding and ventricular arrhythmia (immature weaning) decreased with low‐heparinized isolated left ventricular supports. However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.
Absorption of Insulin in the Peritoneal Cavity in a Diabetic Animal Model
Authors: Waxman Kenneth , Soliman M. Hani , Nguyen Khanh H.
Published: July 2010

Abstract: This study was conducted to determine if different anatomical sites within the peritoneal cavity have different capacities for portal insulin absorption. Diabetic male Sprague‐Dawley rats were studied. They were anesthetized and injected with streptozotocin. Blood glucose was measured before and after insulin (1 U/kg) was applied directly to the omentum, serosal surface of cecum, or parietal peritoneum or injected subcutaneously. In a control group, blood glucose was measured at intervals without administering insulin. In addition, insulin labeled with radioactive iodine (125I) was applied to the same three locations in the peritoneal cavity or injected intravenously. Animals were sacrificed at 1, 5, 15, or 30 mins, and radioactivity was measured in excised livers and in blood samples. Blood glucose in the omental group responded to insulin with a greater hypoglycemic effect than in the peritoneal and control groups. The percentage of radioactivity recovered in liver was significantly higher in the omental than in the serosal and peritoneal groups at 1 and 5 mins. The ratio of liver‐to‐blood radioactivity was also significantly higher in omental than in serosal and peritoneal groups and higher in the serosal than in the peritoneal group at 5 mins. The data suggest that, in this model, the omentum is a better site for insulin absorption than serosa or parietal peritoneum and that significant portal venous absorption of insulin occurs.
Rapid Formation of Multicellular Spheroids of Adult Rat Hepatocytes by Rotation Culture and Their Immobilization within Calcium Alginate
Authors: Yagi Kiyohito , Tsuda Kozo , Serada Masashi , Yamada Chikaomi , Kondoh Akihiro , Miura Yoshiharu
Published: July 2010

Abstract: Tyrosine aminotransferase (TAT) induction and albumin secretion abilities were examined in rat hepatocytes immobilized within calcium alginate; the immobilized hepatocytes lost these abilities within a week. An attempt was then made to immobilize multicellular spheroids of hepatocytes for the purpose of stabilizing the liver functions. Although it takes at least 4 days to form spheroids in the conventional method using monolayer‐cultured cells, in this study we developed a new method for rapid spheroid formation. Isolated hepatocytes were seeded into a polystyrene dish and incubated on a rotary shaker. Hepatocytes started to aggregate after 6 h of the rotation culture, and spheroids approximately 100 μm in diameter formed within 24 h. The immobilized spheroids had higher TAT induction and albumin secretion abilities, which were maintained for a longer time, than the immobilized nonaggregated cells. Further stabilization was observed in immobilized heterospheroids formed in the presence of non‐parenchymal liver cells. This method for the rapid formation of spheroids consisting of hepatocytes and non‐parenchymal liver cells could be utilized in the construction of a bioartificial liver support system.
Transcutaneous Energy Transfer System Performance Evaluation
Authors: Mussivand Tofy , Miller John A. , Santerre Paul J. , Belanger Gaetan , Rajagopalan Kesava C. , Hendry Paul J. , Masters Roy G. , Holmes Kevin S. , Robichaud Raymond , Keaney Marilyn , Walley Virginia M. , Keon Wilbert J.
Published: July 2010

Abstract: A transcutaneous energy transfer (TET) system has been developed to power implantable devices such as artificial hearts, defibrillators, and electrical stimulators. Transcutaneous coupling of power to these implanted de‐vices remains a favorable alternative as percutaneous lines are avoided in order to eliminate the potential of infection and allow patient mobility. In vitro, in vivo, ex vivo, and human cadaver studies of the electrohydraulic ventricular assist device TET have demonstrated that power can be transmitted over a range of skin thicknesses of 3–15 mm and can tolerate radial misalignments of up to 20 mm. Sensitivity to coil separation and radial misalignment variations has been addressed by the development of an auto‐tuning TET. The system has only a 10% attenuation in secondary coil voltage when metallic objects are in contact with the primary coil. The system has demonstrated a power transfer efficiency of 60–80% for power demands from 5 to 70 W. The TET secondary coil will provide an output voltage of 10–25 V for current demands from 0.5 to 4.0 A. TET chronic studies in porcine models have demonstrated no adverse effect to the tissue when up to 40 W of power can be delivered to an implanted load without the tissue‐contacting surface of the coil exceeding 42°C. In conclusion, the TET is a feasible alternative for tether‐free power transmission.
Parathyroid Hormone and T‐Cellular Immunity in Uremic Patients in Replacement Dialytic Therapy
Authors: Angelini Daniela , Carlini Antonio , Giusti Riccardo , Grassi Riccardo , Mei Ermenegildo , Fiorini Italbo , Mazzotta Luisa , Antonelli Alessandro
Published: July 2010

Abstract: We studied 54 patients in replacement dialytic therapy divided into two groups: Group 1, 26 patients with normal parathyroid hormone (PTH) (10–80 pg/ml); and Group 2, 28 patients with elevated PTH (80–400 pg/ml). Total T lymphocytes, CD4, CD8, and CD4/CD8 ratio were evaluated. We found a reduction of total T lymphocytes in both groups compared with controls. A decrease of CD4 and CD4/CD8 ratio with a rise of CD8 occurred in Group 2 but not in Group 1. In Group 2, PTH presented a linear correlation with CD8 and a reverse correlation with total T cells, CD4, and CD4/CD8 ratio. PTH might act on T‐cellular immunity with an immunosuppressive effect from the earlier phases of hyperparathyroidism.
Peracetic Acid and Its Application to Medical Instrument Sterilization
Authors: Malchesky Paul S.
Published: July 2010

Abstract: Peracetic acid is recognized as a powerful germicidal agent. However, heretofore its corrosive nature has prevented its direct use for medical instrument sterilization. A specially formulated buffered peracetic acid sterilant with anticorrosives has been developed for use in the STERIS PROCESSTM. The STERIS SYSTEM 1TM Processor and the STERIS 20TM Sterilant Concentrate have met or exceed the rigorous requirements of the Environmental Protection Agency and Food and Drug Administration for making claims related to sterilization. With this system, medical devices including endoscopes are sterilized and ready for use in less than 30 min.
Effect of Blood Access on the Platelets of Azotemic Patients Initiating Dialysis Therapy
Authors: Yasumoto Naruhiro , Kitamoto Yasunori , Yoshimura Nobuaki , Nakayama Mahito , Sato Tatsuo
Published: July 2010

Abstract: The effect of blood access on platelets and clotting factors was investigated in 46 azotemic patients. Arteriovenous fistula was used in 10 patients (AVF group), and polyurethane double‐lumen catheters were inserted through the subclavian vein in 6 patients (PUS group) or through the femoral vein in 15 patients (PUF group). Indwelling urokinase‐immobilized single‐lumen catheters and double‐lumen catheters were placed in the femoral vein of 5 patients (UKS group) and 10 patients (UKD group), respectively. Blood cell counts, β‐thromboglobulin (β‐TG), platelet factor 4 (PF4), prothrombin time, and activated partial thromboplastin time were measured before insertion while catheters were indwelling and after catheters were pulled out. Although the platelet count decreased to 83% of the initial value during indwelling in the PUF group and 89% in the PUS group, it did not decrease in the AVF, UKS, and UKD groups. There were no differences between the PUF and PUS groups nor between the UKS and UKD groups. Plasma β‐TG increased in the PUF and UKD groups with indwelling catheters but did not change with the AVF. From these results, we conclude that the AVF did not activate platelets, the urokinase‐immobilized catheter activated platelets, and the polyurethane catheter activated and decreased platelets. This might be due to the different surface properties of each blood access. Thus, the urokinase‐immobilized catheter seems to be more favorable than the polyurethane catheter for emergency blood access.
Acetate‐Free Biofiltration in Acute Renal Failure
Authors: Meloni Carlo , Morosetti Massimo , Meschini Luciano , Taccone‐Gallucci Massimo , Casciani Carlo Umberto
Published: July 2010

Abstract: Hemodialysis treatment for acute renal failure is associated with a high incidence of adverse reactions. Hemodynamic stability and adequate correction of acid‐base and hydroelectrolyte imbalance are the main goals of dialytic strategy in acute renal failure. However, the variety of etiology and the diversity of clinical conditions suggest that individualized treatment may be advisable. To this purpose, in 26 patients suffering from “isolated” acute renal failure of different etiologies, we have used acetate‐free biofiltration. We have performed 411 dialyses with an extremely low incidence of symptomatic treatments and remarkable cardiovascular stability. Correction of fluid, electrolyte, and acid‐base imbalance proved excellent. Dialytic efficacy proved adequate. Our data show that acetate‐free biofiltration is an easy technique suitable for individualized treatment and adaptable to changing needs during hemodialysis in patients with isolated acute renal failure.
Multicenter Study with Recombinant Human Erythropoietin
Authors: Tanakay Hiroshi , Kan Eishin , Takegaki Yoshinori , Inariba Hiromi , Yoshimoto Mitsuru , Ohno Yoshioki , Maekawa Masanobu , Tatsumi Noriyuki , Kishimoto Taketoshi
Published: July 2010

Abstract: A multicenter study with recombinant human erythropoietin (rh‐EPO) was carried out. Of 172 hemodialysis patients with anemia selected for the study from 20 hospitals and clinics, 77 were males and 95 females (mean age 53.9 years). A starting dose of 1,500 U of rh‐EPO (Epoetin β) was administered intravenously at the end of every dialysis session. If the efficacy was not acceptable, the dose was increased to 3,000 U. When the target hematocrit was achieved (30%), the total dose was decreased. The results of the study were excellent relative to those of other multicenter studies with regard to efficacy, safety, and changes in laboratory data. The incidence of hypertension was lower in our study compared with other reports because we used a low initial dose. The efficacy of rh‐EPO therapy was determined earlier and more reliably by reticulocytes than by hematocrit or hemoglobin. Prompt iron supplement therapy is recommended with careful observation of serum iron and ferritin.
A Flow Visualization Study of Centrifugal Blood Pumps Developed for Long‐Term Usage
Authors: Araki Kenji , Taenaka Yoshiyuki , Masuzawa Toru , Inoue Kazushige , Nakatani Takeshi , Kinoshita Masayuki , Akagi Haruhiko , Baba Yuzo , Matsuo Yoshiaki , Sakaki Masayuki , Anai Hirofumi , Takano Hisateru
Published: July 2010

Abstract: We have developed centrifugal pumps for long‐term circulatory assistance, with the final goal of a completely implantable ventricular assist device or total artificial heart. The previous model, NCVC‐0, was characterized by a nonseal design and few flow‐stagnating parts and acquired high durability and antithrombogenicity. To improve its pumping performance, NCVC‐0 was modified. In the new model, NCVC‐ I, the profile shape of the impeller was changed from flat to conical, the number of vanes from 4 to 6, and the vane entrance angle from 30° to 60°. A flow visualization study performed by means of a combination of the polystyrene tracer method and the light‐cutting method indicated decreased flow turbulence between vanes in NCVC‐1, which corresponded well with the increased pumping performance. Flow visualization is a useful method to evaluate the design elements that are closely related to the pumping performance of a centrifugal blood pump.
The Renin‐Angiotensin‐Aldosterone System and Hematologic Changes During Pulsatile and Nonpulsatile Cardiopulmonary Bypass
Authors: Goto Masahiro , Kudoh Kazunori , Minami Shigeru , Nukariya Michio , Sasaguri Shirou , Watanabe Mikio , Hosoda Yasuyuki
Published: July 2010

Abstract: The effects of pulsatile and nonpulsatile cardiopulmonary bypass using a roller pump on levels of vasoactive hormones and hematologic changes were studied in 32 patients subjected to elective primary coronary artery bypass graft surgery. Seventeen patients had nonpulsatile perfusion (nonpulsatile group) and 15 patients had pulsatile perfusion (pulsatile group) during the period of cardiac arrest. Vasoactive hormones (plasma renin, angiotensin II, aldosterone, epinephrine, and norepinephrine) were measured in these patients. In order to clarify hematologic changes, plasma free hemoglobin, number of platelets, platelet factor 4, and β‐thromboglobulin were measured. There were no significant differences between the pulsatile and nonpulsatile groups with regard to vasoactive hormones and damage of platelets. In the pulsatile group, however, the rise of plasma free hemoglobin levels was significantly higher than that in the nonpulsatile group during and after cardiopulmonary bypass. We did not see the benefit of pulsatile perfusion using a roller pump on vasoactive hormones. Evidence of increased hemolysis with pulsatile flow was demonstrated in our cases.
Comparison of a New and a Standard Single‐Needle Dialysis System Using a Mathematical Model
Authors: De Wachter Dirk , Verdonck Pascal , Verhoeven Ronny , Hombrouckx Remi
Published: July 2010

Abstract: Two single‐needle dialysis systems are compared for their hydrodynamic and kinetic behavior, the classic double‐headed pump system and a newer hidirectional blood pump. First, discharges and pressures are calculated in a time‐space grid to learn about the flow characteristics of the single‐needle systems. These parameters are important for they control ultrafiltration and clearance rates in the artificial kidney. Also, the influence of different artificial kidneys and expansion chambers on the flow parameters is studied. Second, starting from these results, the removal of urea and creatinine is simulated using a double‐pool model for both a normal dialysis session and an ultrashort daily autodialysis. As a result, the use of a single marker molecule to study or characterize solute removal is questioned. The new blood pump is able to perform dialysis filtering equivalently to the classic system but has its own specific advantages.
Permanent Cardiac Pacing after Cardiac Operations
Authors: Otaki Masaki
Published: July 2010

Abstract: From January 1980 through December 1990, implantation of a permanent pacemaker was performed in 34 patients following open heart surgery. The patients were divided into two groups according to the clinical indications for implantation of permanent pacemakers. Group I (9 patients) had surgical atrioventricular block, and Group 2 (25 patients) had sick sinus syndrome. Tricuspid valve surgery was involved in 67% of Group 1 and 64% of Group 2. Adams‐Stokes syncopal attack was the prime indication for permanent pacing in 100% of Group 1 and in 72% of Group 2. There were 2 operative deaths in Group 1, and no deaths in Group 2 (22% in Group 1 vs. 0% in Group 2, p < 0.005). Causes of the deaths were not related to the pacemaker implantation but to congestive heart failure following surgery. Among 32 survivors, there were 2 late deaths in Group 1, and 4 deaths in Group 2 (25% in Group 1 vs. 16% in Group 2, p < 0.05). The overall actuarial survival rate at 10 years was 82.1 ± 2.8%. However, the actuarial survival rate of patients in Group 1 is 70.2 ± 4.1%, which is statistically less than 85.4 ± 2.2% in Group 2 (p < 0.01). As judged by these results, patients in Group I should be followed on a regular out‐patient basis even if they are asymptomatic and there is no evidence of pacemaker failure.
The PUCA Pump: A Left Ventricular Assist Device
Authors: Verkerke Bart , de Muinck Ebo D. , Rakhorst Gerhard , Blanksma Paul K.
Published: July 2010

Abstract: Left ventricular assist devices (LVADs) that are being used clinically still have specific drawbacks. Therefore, a new concept for mechanical circulatory support was developed, the pulsatile catheter (PUCA) pump. It consists of an extracorporeally placed, pneumatically driven membrane pump that is connected to a valved catheter. Ther catheter is introuced into an easily accessible artery and positioned with its distal tip in the left ventricle. Blood is aspirated from the left ventricle and ejected into the ascending aorta. Potential advantages of the catheter pump are its simple design and its fast application with minimal surgery. Preliminary in vitro tests with a first prototype showed that it is possible to create a pulsatile flow of 3 L/min and proved that further developing the PUCA pump will be worthwhile.
In Vitro Performance of the Baylor/NASA Axial Flow Pump
Authors: Damm G. , Mizuguchi K. , Bozeman R. , Akkerman J. , Aber G. , Svejkovsky P. , Takatani S. , Nosé Y. , Noon G.P. , DeBakey M.E.
Published: July 2010

Abstract: A cooperative effort between Baylor College of Medicine and NASA/Johnson Space Center is under way to develop an implantable axial flow left ventricular assist device (LVAD). The pump is intended as an assist device for either pulmonary or systemic circulatory support for more than 3 months' duration. Currently, in vitro studies are under way to reduce the hemolysis generated by the axial flow pump. A system utilizing a testing matrix has been developed to analyze the effects of different pump parameters on hemolysis. The following parameters are being investigated: impeller blade tip geometry, impeller/flow tube clearance, impeller/stator clearance, number of impeller blades, number of stator blades, and length of the impeller. To date, an index of hemolysis of 0.038 g/100 L has been achieved. The test matrix is not complete, and further improvements are expected.