bluuebunny/crossref_metadata_2025 huggingface dataset:
Angiographic and Pathological Studies on Regression of Coronary Atherosclerosis of FH Patients Who Received LDL‐Apheresis Treatment
Authors: Koga Nobuhiko , Iwata RYasushi , Yamamoto Akira
Published: July 2010

Abstract: We report on the most recent data confirming the angiographic and pathological efficacy of LDL‐apheresis for coronary atherosclerosis of a familial hy percholes‐terolemia (FH) patient using collected data of a large number of cases and especially of one autopsy case, Changes in coronary artery stenosis have been assessed angio‐graphically in 37 FH patients in the LDL‐Apheresis Regression Study (LARS) group of 13 institutions in Japan. Definite regression was observed in 21 segments by visual and computer analysis. Fourteen of 37 patients (37.8%) who had received LDL‐apheresis treatment in combination with cholesterol‐lowering drugs had at least one regressed segment without any progressed segment. We pathologically examined at autopsy the coronary arteries in one FH patient who had received long‐term LDL‐apheresis therapy before death. The results revealed the process of scarring of atheromatous plaque, suggesting pathological regression correlated with the angiographic regression shown in serial angiograms taken during LDL‐apheresis treatment. It was further suggested that the formation of an eccentric thickened wall lesion rich in collagen fiber prevented atheromatous plaque from tearing off. Such tearing off might lead to an acute coronary event. Aggressive cholesterol‐lowering therapy based on LDL‐apheresis can induce both angiographic and pathological regression in coronary atherosclerosis of FH patients.
Noninvasive Monitoring of Rotary Blood Pumps: Necessity, Possibilities, and Limitations
Authors: Schima Heinrich , Trubel Wolfgang , Moritz Anton , Wieselthaler Georg , Stohr Hans G. , Thoma Herwig , Losert Udo , Wolner Ernst
Published: July 2010

Abstract: Although rotary blood pumps do not contain an inherent mechanism for adaptation to physiological flow necessities, hitherto only a few efforts have been made to obtain robust monitoring and control methods. This paper discusses the necessity of noninvasive monitoring of such pumps and the crucial points of sensor selection and development. A strategy of monitoring atrial pressure out of the data obtained by the collapse of the atrial wall around the inflow cannula and initial results on animal tests and computer simulation of this method are discussed. This approach might lead to reliable and demand‐responsive controllers, if some basic criteria are fulfilled.
KT/V and Protein Catabolic Rate Determination from Serial Urea Measurement in the Dialysate Effluent Stream
Authors: Garred Laurie J. , DiGiuseppe Bonny , Chand Winston , McCready William , Canaud Bernard
Published: July 2010

Abstract: A bloodless technique of evaluating protein catabolic rate (PCR) and KT/V (K, clearance; T, dialysis time; V, urea distribution volume) in hemodialysis patients is presented based on serial measurement of urea in the dialysate effluent stream. PCR follows from equating urea generation and urea removal over a 7 day cycle, changes in body stores being comparatively negligible: PCR = 0.026 [U1+ U2+ U3]/BWdry+ 0.17, where Ui is the amount of urea in mmol appearing in the dialysate for each session in the 7 day period. KT/V is obtained from the slope of the natural logarithm of spent dialysate urea concentration‐time plot: KT/V = [‐ slope. T+ 3. ΔBW/ BWdry]/[1–0.01786 *T(hr)], where ΔBW = amount ultrafiltered in liters. The dialysate‐based approach was validated and compared with conventional urea kinetic modeling (UKM) for 17 patients studied for three consecutive dialyses. The dialysate‐based and UKM values of PCR agreed well when in vivo clearance values based on total dialysate collection were used for UKM. KT/V values agreed poorly on a session‐by‐session basis but were nearly equivalent when averaged for the three dialyses of the week. These findings lay the foundation for UKM automation with a urea sensor in the effluent dialysate stream.
Evaluation of a Polyepoxy Compound Fixed Biological Vascular Prosthesis and an Expanded Polytetrafluoroethylene Vascular Graft
Authors: Hata Cary , Wang Edwin , Noishiki Yasuharu , Tomizawa Yasuko , Tu Roger , Sung Hsing W. , Quijano Rodolfo C.
Published: July 2010

Abstract: Antithrombogenicity is one essential requirement for the successful use of small caliber vascular prostheses. In this study, a polyepoxy compound fixed, heparinized 4 mm diameter Baxter Denaflex vascular graft was evaluated against a 4 mm diameter Gore‐Tex expanded polytetrafluoroethylene (ePTFE) vascular graft in the canine model. In addition to the thromboresistant characteristic conferred by heparinization, the crosslinking agent allowed the Denaflex graft to retain the original color of the native artery. Six centimeter long graft segments were implanted into the carotid arteries bilaterally in 5 dogs. The patency rate at 3 months for the Denaflex graft was 100% (five out of five) whereas in the control ePTFE graft, it was 40% (two out of five). The explanted Denaflex grafts exhibited softness and flexibility, and their luminal surfaces maintained a white color like that before irnplantation. To the contrary, the patent ePTFE grafts felt hard, and red thrombi covered large portions on their inner surfaces. Under microscopic observation, neointima formation was limited to regions near the anastomotic sites for both types of grafts. This experiment showed that the Denaflex vascular graft has an excellent antithrombogenic property and has a compliance similar to native arteries.
After a Cardiomyoplasty, Collaterals from Skeletal Muscle Form to Chronic Ischemic Myocardium
Authors: Buckman Peter D. , Mannion John D. , Magno Michael , DiMeo Fred , McHugh Mary
Published: July 2010

Abstract:We measured the collateral formation between skeletal muscle and the heart after a latissimus dorsi cardiomyoplasty in an animal model that contained normal, chronic ischemic, and infarcted myocardium. The area at risk for ischemia was 27.0 ± 3.2% of the left ventricular mass (n = 10, mean ± SE). In five animals the risk area developed predominantly into chronic ischemic myocardium; in five others the risk area became an infarct. The collateral blood flow from the skeletal muscle to chronic ischemic myocardium (6.05 ± 1.36 m1/100 glmin, n = 5) was higher than flow to the infarct (0.46 ± 0.31 m1/100 g/ min, n = 5). The collateral blood flow to normal myocardium was minimal (0.04 ± 0.01 m1/100 gimin). The collateral blood flow appeared to be concentrated in the outer half of the left ventricular wall, with the epicardium having a higher skeletal muscle derived collateral blood flow than endocardium (p < 0.05). We conclude that after a cardiomyoplasty a collateral blood flow, which approaches clinical significance, is preferentially established between skeletal muscle and chronic ischemic myocardium. Enhancement of this collateral blood flow might provide a means to revascularize patients with presently inoperable coronary disease.
Oral Treatment for Jaundice Using Immobilized Bilirubin Oxidase
Authors: Soltys Paul J. , Mullon Claudy , Langer Robert
Published: July 2010

Abstract: Jaundice is characterized by an excessive accumulation of bilirubin in the blood and tissues. A novel approach to reduce plasma levels of bilirubin by blocking its enterohepatic circulation was investigated. The treatment consisted of oral administration of immobilized bilirubin oxidase, which could oxidize bilirubin in the intestine to less toxic and more water‐soluble products. In vivo administration of 0.1 to 2.0 mg/day of immobilized enzyme over a four‐day period to chronically jaundiced Gunn rats effectively lowered plasma bilirubin levels, but only when the molar ratio of total serum bilirubin to rat serum albumin (BIRSA) was larger than 0.35. Plasma bilirubin concentration decreased in that group from an initial value of 11.3 to 6.3 mg/dl (–40%, n = 5) after eight days. This decrease was statistically significant (p < 0.05 by Student's rtest). However, administration of bilirubin oxidase to rats with a B/RSA ratio less than 0.35 (n = 10) resulted in no statistically significant change in plasma bilirubin concentration.
Effects of a New Bone‐Inducing Biomaterial on Mesenchymal Cells In vitro
Authors: Joos U.E. , Fehrenbach E. , Hogh‐Janovsky K. , Wimmer F.M. , Schneider E.M. , Schmidt K.H.
Published: July 2010

Abstract: A purified bone‐inducing protein complex (BIC), isolated from bovine bone and causing de novo bone formation in vivo, induces defined effects on rat mesenchymal cells in vitro. Spindle‐like mesenchymal cells growing in monolayers change to polygonal cells, forming a multilayered growth pattern. The mesenchymal cells acquire alkaline phosphatase activity. Upon culture with BIC, the typical collagen Type III deposition of these mesenchymal cells is remarkably reduced whereas the collagen Type I expression remains unaffected. All these in vitro effects are consistent with the strong bone‐forming capacity of BIC in vivo. A combination of two cytokines, transforming growth factor β l (TGFβl) and epidermal growth factor (EGF), shows a similar activity to BIC. Neutralizing anti‐TGFβ antibodies interfere with all in vitro effects of BIC. The neutralization of BIC and the inductive capacity of the combination of TGFβl plus EGF point to the substantial role of TGFβ or TGFβ‐like molecules in BIC; whether the active polypeptides are identical to TGFP or somewhat structurally homologous to TGFβ remains to be elucidated.
Thrombus with Infection in Total Artificial Heart Animals
Authors: Chiang Bang Y. , Olsen Donald B. , Burns Gregory L. , Pantalos George M. , Everett Scott , Dew Pamela A. , Tatsumi Eisuke , Rowles John R. , Mohammad Fazal
Published: July 2010

Abstract: From January 1980 to December 1990, several types of total artificial hearts were implanted into 378 animals. In a retrospective study of these animals. 147 (39%) were found to have thrombus with infection (T&I). The criteria for diagnosis was thrombus formation in the artificial heart and a positive blood culture. The most common pathogen isolated from T&I animals was Pseu‐domonas species. Concurrent skin lesions and contamination from the pressure lines may be the primary sources of infection, but bacterial translocation from the intestine is another possible route. The main pathological findings at necropsies of artificial heart animals with T&I were associated with sepsis, congestive heart failure, infected thrombus, thromboembolism, and multiple organ infarctions. Most thrombi appeared to have originated from valve junctions and connectors. On the basis of these observations, a possible mechanism for pathogenesis of T&I has been proposed. The results suggest that design improvements and surface modifications to reduce thrombosis are important factors that should be carefully considered. Similarly, it is important to eliminate the route of entry of pathogenic microorganisms. These findings imply that bacterial interaction with thrombus, device‐related bacterial colonization, and host immunomodulation and gut barrier function following artificial heart implantation need further investigation.
Diminished Release of Atrial Natriuretic Factor in Calves with a Total Artificial Heart
Authors: Windberger Ursula , Urbanek Peter , Vierhapper Heinrich , Wieselthaler Georg , Dolezel Svatopluk , Nowotny Peter , Trubel Wolfgang , Dostal Miles , Vasku Jaromir , Losert Udo
Published: July 2010

Abstract: Venous hypertension after total artificial heart (TAH) replacement, a common problem in humans as well as experimental animals, is thought to be related to reduced release of atrial natriuretic kictor (ANF) due to atrial damage. To verify this hypothesis, we stimulated the release of ANF in 6 calves before (— 7 days) and after TAH replacement (+ 25. +50, +80. and + 100 days) by therapid(+= 10 min)infusion of 2 Lof Kinger's solution. In normal calves (‐7 days) this procedure induced a rise in plasma concentration of ANF from 18.5 ± 12 to 31.6 ± 12 pmol/L (p < 0.05). After TAH the ANF release continuously decreased (analysis of variance. p < 0.02). Thus. ANF increased by 9.8 ± 9.3. 6.8 ± 17.5. 0.4 ± 5.2, and 0.5 ± 3.2 pmol/L at days 25. 50, 80, and 100, respectively. The central venous pressure increased by 3.4 ± 1.5 mm Hg (before TAH) and by 6 ± 2.9 mm Hg (after TAH) during this procedure. A decrease in plasma concentrations of aldosterone, most likely due to extracellular volume expansion and a decrease in total protein plasma concentrations and in hematocrit due to the dilution of blood, was seen in each experiment. Necropsy demonstrated massive atrial dilatation and myocairdial dystrophy with atrial fibrosis. ANF granules were present to a small extent in every calf. We conclude that rapid intravenous infusion is an adequate stimulus to release ANF in normal calves. AfterTAH implantation the release of ANF by high venous pressure declines although ANF granules are still present in the damaged atrial stumps. Therefore. the loss of stimulated ANF could contribute to the observed increase in venous pressure in TAH calves although other pathophysiologic mechanisms cannot be excluded.
Development of a Totally Implantable Electromechanical Total Artificial Heart: Baylor TAH
Authors: Takatani Setsuo , Shiono Motomi , Sasaki Tatsuya , Glueck Julie , Noon George P. , Nosé Yukihiko , DeBakey Michael E.
Published: July 2010

Abstract: A totally implantable, one‐piece. electromechanical total artificial heart (TAH) intended for permanent human use has been developed. It consists of left and right pusher‐plate pumps (63 cc design stroke volume) sandwiching a thin center piece with a compact electromechanical actuator. The pusher‐plates are shaped conically to accommodate an actuator in the space between them. The actuator consists of an efficient and durable planetary roller screw and direct current brushless motor. The left master alternate pumping mode was implemented utilizing the left pump pusher‐plate position signal. The blood‐contacting surface was coated with a dry gelatin to yield long‐term clot‐free performance. Trileaflet tissue valves of 27 and 23 rnm are used in the inflow and outflow ports. The diameter and thickness of the TAH are 97 and 82 mm, the overall volume is 510 cc, and the weight is 620 g. Anatomic fit was confirmed in 26 heart transplant recipients (body weight 78 kg and surface area 2 m?) without compressing adjacent organs. The pump performance study revealed that the TAH can yield outputs of 3–8 L/ min against the 100 mm Hg afterload with 1–10 mm Hg filling pressure. The input power to the motor ranged From 7 to 12 W, with an efficiency of 18% to 14%. A one‐week in vivo calf study demonstrated adequate performance of the TAH, particularly the regulation of atrial pressures. Good anatomic fit and good biocompatibility were also demonstrated.
In vitro Buffering Capacity of Residual Peritoneal Dialysate Fluid: Implications for Peritoneal Dialysis Therapy
Authors: Ahmed M.I. , Rawal P.A. , Patel N.M. , Yu A.W. , Abraham M. , Harvey V.C. , Ing T.S.
Published: July 2010

Abstract: The buffering capacity of the residual peritoneal dialysate fluid from each of 5 patients undergoing continuous ambulatory peritoneal dialysis was assessed by titrating with fresh, conventional, acidic, and lactate‐containing peritoneal dialysis solutions. It was found that residual fluids had considerable buffering capacity.
Properties of Hemoglobin and Dextran‐Hemoglobin Rightshifted by Oxidized Inositol Tetrakisphosphate
Authors: Xue Hong , Wu Xiang‐Fu , Wong J. Tze‐Fei
Published: July 2010

Abstract: Phytate was digested by wheat bran phytase to yield inositol tetrakisphosphate. Periodate‐oxidized inositol tetrakisphosphate (oxyIP4) was coupled by means of reductive alkylation to hemoglobin and the covalent dex‐tran‐hemoglobin conjugate to yield the rightshifted (rs) compounds rsHb and rsDxHb, respectively. The variations of the oxygen dissociation curves of these molecules with pH and temperature were compared to those of hemoglobin. The variations with pH were found to be less pronounced for these rightshifted forms. An extensive decrease in the half‐saturation oxygen tension was observed, however, with both rsHb and rsDxHb, as in the case of unmodified Hb. Modification of hemoglobin by oxyIP4 at the polyphosphate site was suggested by the lack of a further rightshifting effect of phytate on rsHb, and by the similarity between the difference spectrum of rs‐methemoglobin and the difference spectrum induced by the addition of phytate.
Wearable Air Supply for Pneumatic Artificial Hearts and Ventricular Assist Devices
Authors: Sipin A.J. , Fahrey W.J. , Smith S.H. , Doirssourd J.D. , Olsen D.B.
Published: July 2010

Abstract: An experimental wearable air supply for pneumatic artificial hearts and ventricular assist devices has been built and tested. The unit eliminates the need for tethering to a large, stationery driver. The miniaturized air supply is designed for ambulatory patients with implanted pulsatile pneumatic total artificial hearts (TAH) or pneumatic left‐ventricular assist devices (LVAD), to permit mobility in clinical and home settings. The device has major short‐term utility as a supply for pneumatic TAH or VAD bridges in patients awaiting heart transplants. The system design for the wearable driver includes a novel, fast rotary compressor, driven by a brushless direct current (DC) motor to supply air to the ventricle through an electromagnetically actuated directional valve, all controlled by a microcomputer. Stroke volume from 0 to 200 cc; pulse rate from 60 to 160 bpm, and duty cycle from 33% to 50% are selected on a keyboard, and the selected or measured parameters can be shown on a liquid crystal display. For control of delivery from a single ventricular assist device, stroke volume is controlled by variation of compressor speed. In the wearable air supply for a TAH, a single compressor drives both ventricles alternately through a double‐acting directional valve. Air volume delivered to the left ventricle is adjusted by variation of compressor speed, and air volume to the right ventricle by variation of ejection time. The effect on blood flow rate of the lower impedance to the right ventricle is compensated by provision of a two‐stage compressor, in which a single stage drives the right ventricle, and both stages connected in parallel drive the left ventricle. The overall dimensions of the prototype air supply for driving either a TAH or LVAD are 4.5 by 7.8 by 4.5 inches, including an emergency battery with a duration of 15 to 30 min depending on load. The weight is presently 5.5 Ib, but this will be reduced in a production design and for a dedicated LVAD air supply. The size and weight of a separately worn, rechargeable battery pack depend on the load and desired duration of operation.
Regulation of Differentiation and Proliferation of Rat Hepatocytes by Lactose‐Carrying Polystyrene
Authors: Kobayashi A. , Goto M. , Sekine T. , Masumoto A. , Yamamoto N. , Kobayashi K. , Akaike T.
Published: July 2010

Abstract: We noticed that hepatocytes recognize the structure of oligosaccharides via asialoglycoprotein receptors and synthesized lactose‐carrying styrene polymer (PVLA) as an asialoglycoprotein model. We found that the regulation of differentiated function and proliferation of hepatocytes that were cultured on polystyrene dishes can be achieved by varying the amount of PVLA coated on the dishes. The 3H‐thymidine uptake of cultured hepatocytes is low for cells cultured on dishes coated with high amounts of PVLA in which the hepatocytes are round and is highest for those cultured on dishes with a low PVLA coating level in which the hepatocytes are spread in shape.

Moreover, bile acid release as a typical differentiated function of hepatocytes was maintained at higher levels in hepatocytes attached on dishes coated with a high level of PVLA. Our results indicated that regulation of differentiated function and proliferation in hepatocytes could be achieved by specific ligand‐mediated recognition of microscopic surface structure. Thus, it may be possible to regulate proliferation and differentiation of hepatocytes by design of the culturing substrata.
Effects of Pyridoxalated Hemoglobin Polyoxyethylene Conjugate and Stroma Free Hemoglobin on Pulmonary Vascular Responsiveness to Vasoactive Substances in Isolated Perfused Rat Lungs
Authors: Gotoh Keiji , Matsumura Hiroaki , Morioka Tohru , Nishi Katsuhide
Published: July 2010

Abstract:We examined the effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances in isolated perfused rat lungs. The lungs isolated from rats were perfused with 6% PHP, 6% SFH, or 6% hydroxyethylstarch (HES) solution, and the effects of intrapulmonary arterial injection of norepineph‐rine (NE), angiotensin II (ANG‐II), acetylcholine (ACh), and nitroglycerin (NG) were examined by measuring per‐fusion pressure. NE and ANG‐II produced a dose‐dependent increase in perfusion pressure in all groups. The NE response in the PHP‐ or SFH‐perfused group was significantly larger than that in the HES‐perfused one. ACh decreased perfusion pressure in both PHP‐ and HES‐perfused groups but increased perfusion pressure in the SFH‐perfused group. NG decreased perfusion pressure in all groups. Present results indicate that pulmonary arterial responses to endothelium‐derived relaxing factor (EDRF) induced by ACh would not be affected in the presence of PHP.
Plasma Lipids and Fatty Acid Levels in Chronically Uremic Patients Undergoing Blood Purification with Different Methods
Authors: Marangoni Roberto , Civardi Fernando , Suuino Renato , Colombo Roberto , Marangoni Franca , Mosconi Cristina , Galli Claudio
Published: July 2010

Abstract: Levels of plasma lipids and the fatty acid composition of major plasma lipid classes have been determined in chronically uremic patients before and after treatments with hernofiltration, high efficiency paired filtration dialysis, or acetate‐free biofiltration. The major findings are a decrease of triglycerides and an increase of total free fatty acids (FFAs) at the end of the dialytic session—already reported in the literature—that do not appear to be strictly dependent on heparin administration. The changes in the plasma concentrations of selected saturated and polyunsaturated fatty acids, which may contribute to alteration of functional parameters in the cardiovascular system in dialyzed patients, are different in the various types of techniques.
Iontophoresis of Drugs in the Bladder Wall: Equipment and Preliminary Studies
Authors: Lugnani Franco , Mazza Giorgio , Cerulli Nicola , Rossi Cino , Stephen Robert
Published: July 2010

Abstract: lontophoresis is the active transport of ions into tissues by means of an electric current: Ji=–DiΔCi/Δx+DizeECi/kT. Where Ji is the total ionic flux, Di the diffusion coefficient, Ci the concentration, z the valency, and E the electric field. The first expression on the right side of the equation is Fick's law of diffusion and approaches zero for bladder mucosa, which leads to uncertain results following intravesical administration of various therapeutic agents. The application of an electric field will potentially accelerate drug administration into the bladder wall in a controllable manner. To evaluate this concept, an appropriate source of electric current and electrodes was fabricated; then, studies were conducted in human cadaveric bladders and clinical trials in human subjects. Ionized dyes were applied in duplicate to 10 fresh cadaveric bladders. Electric currents (3.5–5.0 mA) were applied for 20 min to 10 solutions, and no current was used in 10 controls. Twenty‐eight patients had 100 ml solutions of 1% mepivacaine or lidocaine with epinephrine infused into their bladders prior to endoscopic resections. Twenty‐two patients received currents of 10–20 mA for 10–20 min, and 6 controls had either no drugs or a current of reverse polarity applied. Visually and on microscopy, the 10 control cadaveric bladder surfaces demonstrated only faint staining of the surface mucosa whereas the experimental surfaces showed full‐thickness staining of the mucosa extending into the muscularis. The 6 control patients required supplemental anesthesia or abandonment of the operative procedure. Of the 22 experimental subjects, 16 tolerated procedures with up to 25 g of tissue removed by diathermic resection.
Peritoneal Dialysis for the Removal of Protein‐Bound Markers of Hepatic Insufficiency
Authors: Sarnatskaya V.V. , Nikolaev V.G. , Osipova L.A. , Ivanov A.I. , Maslenny V.N. , Ivanyuk A.A. , Yushko L.A.
Published: July 2010

Abstract: The addition of human serum albumin (HSA) to peritoneal dialysate increases the clearance of bilirubin in rats suffering from obstructive jaundice. The acceptor properties of the fluid can be enhanced by using HSA that does not contain standard stabilizing additives and has been purified by further adsorption on activated carbon. Bilirubin‐containing dialysate fluid, as well as the ascitic fluid of cirrhotic patients, can be regenerated by a combination of membrane ultrafiltration and carbon adsorption. These observations suggest a potentially useful scheme for continuous, regenerative peritoneal dialysis in the treatment of hepatic insufficiency.
Evaluating the Flow Characteristics of Artificial Pumping Devices Using Nuclear Scintigraphsy
Authors: Christensen Carl W. , Gao Hua , Smith Luther M. , Krymkowski Mark G. , Schmidt Donald H.
Published: July 2010

Abstract: The design and development of artificial blood pumps require qualitative and quantitative data relative to pump filling, ejection, and wall motion in order to optimize the design and maximize the pattern of blood flow through the pump. To assist in the development of an artificial heart, we utilized radionuclide scintigraphy and a high‐resolution gamma camera to evaluate the flow patterns through the pump. We performed a comparative analysis of the flow patterns in a pneumatically driven ventricular assist device (Sarns/3M VAD) and the electrically driven Milwaukee Heart. These analyses disclose some significant differences between the two devices with regard to the blood sac compression patterns and ejection as well as valvular regurgitation. On the basis of these findings, nuclear scintigraphy for analyzing fluid shear stress and flow dynamics seems a useful technique for evaluating blood flow through artificial blood pumps. Because the procedure does not require a translucent casing or direct contact with the device being studied, it would be especially useful in evaluating artificial blood pumps implanted in patients with heart failure.
Surgical Treatment for Aneurysms of the Descending Aorta Using Temporary Perfusion by a Centrifugal Pump: Clinical Analysis of 33 Cases
Authors: Ataka Keiji , Okada Masayoshi , Yoshimura Naoki , Kujime Keiichirou , Azami Takashi , Ota Toshiaki , Yamashita Chojiro
Published: July 2010

Abstract: Since 1987, 33 patients have undergone surgery at Kobe University Hospital for aneurysm of the descending aorta using left heart bypass with a heparin‐coated centrifugal pump and heparin‐coated tubes. Sixteen patients had true aneurysms of the descending thoracic aorta, 7 had thoracoabdominal aneurysms, and 10 had aortic dissection (DeBakey's Type III). Heat exchangers and oxygenators were not included in the bypass circuit in any of the cases. Perfusion time was from 42 to 205 min (average 90 min). Left heart bypass was established with 1 mg/kg of systemic heparinization in 5 cases, 0.5 mg/kg in 5 cases, and 0 mg/kg in 23 cases. There were no complications such as perioperative embolism, acidosis, or hypothermia. During aortic cross‐clamping, the arterial pressure of the lower extremity was maintained above 70 mm Hg, but there was no relationship between the distal perfusion pressure and bypass flow. The urine output during left heart bypass was related to the distal perfusion flow by centrifugal pump. Of 23 patients who underwent bypass with less than 40 ml/kg/min of distal perfusion flow, 7 showed transient renal dysfunction post‐operatively, and 1 developed postoperative renal failure. The other patients who were bypassed with over 40 ml/kg/min of pump flow stayed in the normal range of renal function. Postoperative paresis occurred in 2 patients, who were also perfused with less than 40 ml&kg/min of bypass flow. It could be concluded that left heart bypass by centrifugal pump is safe and acceptable as a circulatory support in the surgical treatment of aneurysm of the descending aorta. In addition, during such assistance, more than 40 ml/kg/min of perfusion flow is recommended to maintain the distal circulation and to prevent ischemic renal damage and spinal cord injury.
Comparison of Pig Hepatocyte Isolation Using Intraoperative Perfusion without Warm Ischemia and Isolation of Cells from Abattoir Organs after Warm Ischemia
Authors: Gerlach Jörg , Klöppel Karolin , Schön Michael R. , Brombacher Jochen , Courtney James M. , Unger Juliane , Neuhaus Peter
Published: July 2010

Abstract: Enzymatic hepatocyte isolation using warm ischemic pig livers from an abattoir was compared with isolation using in situ perfused organs. Using organs from animals of 30 kg body mass (BM), the intraoperative perfusion showed superior results. The use of livers from abattoir pigs of 40–50 kg BM after warm ischemia resulted in a lower yield of hepatocytes and in high rates of injured cells. The mean yield in the intraoperative perfusion group was 68 ± 11% (wet weight), the maximum yield in the abattoir organ group was 58%. The mean viability in the intraoperative perfusion group was 65 ± 14% (trypan blue) compared with a maximum viability of 39% in the abattoir liver group. Additional purification by density gradient centrifugation improved the viability of the abattoir liver group to a mean of 95% (trypan blue). The use of pig livers from large abattoir animals required additional purification steps to improve viability since the cell yield is considerably lower than with intraoperative organ perfusion. In general, hepatocyte isolation from abattoir organs is not recommended.
Clinical Trials for Removal of Bilirubin by High‐Capacity Nonionic Adsorbent
Authors: Chen Chang‐zhi , Yu Yao‐Ting , Song Ji‐chang , Yuan Ping , Li Tao , Du Zhi
Published: July 2010

Abstract: To remove bilirubin from patients with hyperbilirubinemia, nonionic macroporous adsorbent NK‐110 was tailor‐made from styrene and divinyl benzene at Nankai University. Five patients were perfused through shunts filled with 500 ml of the above adsorbent. After 2 h of hemoperfusion, total bilirubin decreased within the range of 22–51%. During the treatment, no noticeable changes in electrolytes, urea nitrogen, serum glutamicpyruvic transaminase (SGPT), TTT, and amino acid concentrations were observed. Platelet depletion was satisfactory. Hemoglobin, white cell count, globulin, and albumin showed no remarkable changes. The nonionic adsorbent shows a high efficacy for bilirubin removal and has a great potential for future clinical applications.
Open‐Loop Analysis of Circulatory System in Awake Live Animals: Relations between Mixed Venous Saturation (SvO2) and Hemodynamic Parameters
Authors: Takatani Setsuo
Published: July 2010

Abstract: In order to derive quantitative relations between the mixed venous hemoglobin saturation (SvO2) and hemodynamic and metabolic parameters in awake live animals, biventricular bypass experiments were con‐ducted in goats using a pair of pneumatic artificial hearts. The artificial hearts were used to bypass continuously the fibrillating ventricles, to control precisely the pump output, and to derive open‐loop responses of the peripheral circulatory system. The specially developed reflection‐type optical sensors were mounted on each artificial heart to measure continuously arterial and mixed venous SO2 and hemoglobin content ([Hb]), which in combination with pump output data oxygen consumption of the animal was derived on‐line for a maximum duration of 40 days. The SvO2 sensitively reflected the changes in respiratory status, [Hb], pump output, and oxygen consumption. The SvO2 was linearly related to the oxygen consumption but showed nonlinear relation to the pump output. The exercise study revealed that the SvO2 level may be used to detect the anaerobic threshold. The SvO2 is a useful parameter to evaluate circulatory status of the patients.
In Vitro Hematological Testing of Rotary Blood Pumps: Remarks on Standardization and Data Interpretation
Authors: Mueller M.R. , Schima H. , Engelhardt H. , Salat A. , Olsen D.B. , Losert U. , Wolner E.
Published: July 2010

Abstract: Pump test procedures using blood will have to meet several standards not only to obtain reliable results in vitro but also to allow comparison of results of different investigators. This article reviews some of the issues that should be considered in pump testing, especially referring to the discussions held at the International Workshops on Rotary Blood Pumps in 1988 and 1991. The test loop itself should meet some requirements such as constant physiological temperature, standardized circulating volume, control of pressure and flow, and exact definition of the blood‐contacting surface. Specifications have to be made concerning the test fluid blood, including sampling technique, anticoagulation, blood gases, pH, and glucose level. Only fresh blood should be used. Heparin is recommended for anticoagulation because it will be used also in vivo. Different procedures for cleaning and rinsing of plastic materials for reuse are mentioned. Bacterial overgrowth, which can lead to extreme oxygen consumption and acidosis, may be avoided through addition of antibiotics (e.g., gentamicin). To be able to compare data of the different working groups, a new modified index of hemolysis (MIH) has been defined.
Development of an All‐in‐One Percutaneous Cardiopulmonary Support System
Authors: Fukui Yasuhiro , Kawamura Tsuyoshi , Higami Tetsuya , Funakubo Akio , Sakuma Ichiro
Published: July 2010

Abstract:This paper deals with development of an all‐inone percutaneous cardiopulmonary support (PCPS) system. In recent years, PCPS has been used for the treatment of acute myocardial infarction. A prototype of a compact all‐in‐one PCPS system was developed. The system contains a centrifugal pump and an extra‐capillary flow‐type membrane lung in one body. The system has a priming volume of 250 ml, which allows for PCPS with no additional blood. The in vitro tests and an ex vivo test were conducted. The system produces 1.6–5 L/min of flow in the experiments. The O2transfer rate was 310 ml/min, and the CO2transfer rate was 300 ml/min at a blood flow rate of 5 L/min. This device is compact, requires less priming volume than a standard system, and is easy‐to‐handle in the experiments. The system is considered applicable to percutaneous cardiopulmonary support.
Chronic Effects of a Cardiac Assist Device on the Bulk and Regional Mechanics of the Failed Left Ventricle in Goats
Authors: Nakamura Takao , Hayashi Kozaburo , Seki Junji , Fukuda Sachito , Noda Hiroyuki , Nakatani Takeshi , Takano Hisateru , Akutsu Tetsuzo
Published: July 2010

Abstract: Pneumatically driven, diaphragm‐type left ventricular assist devices (LVADs) were implanted into 8 goats with profound induced infarction to the left ventricle by using multiple ligations of the left anterior descending (LAD) coronary artery as well as small arteries in the LAD distribution area. Left ventricular diameters, regional myocardial segment lengths, and wall thicknesses were measured by sono‐micrometers. After left ventricular function seemed to be recovered, the goats were weaned off the LVADs after a gradual decrease of pump bypass flow over several days. Thereafter, hemodynamic and cardiac parameters were observed for about I month more. Three animals recovered successfully owing to the LVAD pumping. Before starting pump‐weaning procedures, the bulk mechanical work (BMW) done by the left ventricle during LVAD pumping and under temporary pump‐off conditions was 0.08 ± 0.01 (mean ± SE) and 0.22 ± 0.01 W/100 g left ventricular weight (LVW), respectively, while the regional mechanical work done by the normal myocardium (RMWn) was 1.5 ± 0.4 and 4.3 ± 0.9 mW/cm3 during pumping and under temporary pump‐off conditions, respectively. BMW and RMWn values obtained under pump‐on conditions both increased gradually during the weaning process. Even after pump removal, they continued to increase and reached constant values of about 0.3 W/100 g LVW and 10 mW/cm3, respectively, around 2 weeks after pump removal. Although the myocardium in the infarction area did no work for the first several days after surgery, it recovered to do some external work with the aid of LVAD pumping. However, recovery of left ventricular function owed more to compensatory increases in pumping ability of the remaining normal myocardium than to recovery of the damaged myocardium. The LVAD could salvage severely damaged hearts unless the infarction area exceeded 50% of the left ventricular wall.
Baylor Gyro Pump: A Completely Seal‐less Centrifugal Pump Aiming for Long‐Term Circulatory Support
Authors: Ohara Yasuhisa , Sakuma Ichiro , Makinouchi Kenzo , Damm George , Glueck Julie , Mizuguchi Kazumi , Naito Kozo , Tasai Kimitaka , Orime Yukihiko , Takatani Setsuo , Noon George P. , Nosé Yukihiko
Published: July 2010

Abstract: A seal‐less centrifugal pump aiming for long‐term circulatory support has been developed. In this model, shaft seals that cause thrombus formation and blood leakage were eliminated. A brushless direct current motor was incorporated as a driving unit, and pivot bearings were used to support the impeller. With reference to its motor‐driven system, this pump was named the M‐Gyro Pump. The first model (M1) yielded an index of hemolysis of 0.005 g/100 L using bovine blood and demonstrated satisfactory performance as a right heart assist for 2 days (4 L/min, 60 mm Hg, 1,800 rpm). The second model (M2) has been developed for left heart assist by employing a stronger motor. The pump capacity was improved to 6 L/min against 240 mm Hg at 1,800 rpm, but significant heat generation was observed. By optimization of motor efficiency, the M2 model can be improved to meet the requirements of a pump for left heart assist.
In Vitro Investigation of Thrombogenesis in Rotary Blood Pumps
Authors: Schima Heinrich , Siegl Helga , Mohammad Syed F. , Huber Leopold , Müller Michael Rolf , Thoma Herwig , Wolner Ernst
Published: July 2010

Abstract: Thrombus formation at sealing and stagnation areas remains a major problem in the development of rotary blood pumps. Until now, the complex phenomena could only be studied in vivo. In this study, an in vitro mock circulation previously used for hemolysis studies was adapted for thrombosis evaluation. Blood was collected in the slaughterhouse with strict avoidance of air contact and was heparinized (1.5 U heparin/ml blood; activated coagulation time [ACT]: initially, 140–180 s; after collection, 400–600 s). During the test, the ACT decreased gradually. The tests were stopped after 90 to 180 min at an ACT of 1.5 times the initial value. Thrombus formation was observed at the same locations as observed in left‐heart assist devices (sealing area, connecting bolts, and stagnant water areas at connectors). The thrombi were similar in shape, color, and histology to those found after 2 to 4 days in vivo. This test provides a valuable tool for evaluating thrombus formation in prototypes and screening tests of different rotary pump designs.
Biocompatibility of Leukocyte Removal Filters during Leukocyte Filtration of Cardiopulmonary Bypass Perfusate
Authors: Gu Y.J. , Obster R. , Haan J. , Huet R.C.G. Gallandat , Eijgelaar A. , van Oeveren W.
Published: July 2010

Abstract: To evaluate the biocompatibility and the efficacy of leukocyte removal filters, we performed a prospective study by using the cardiopulmonary bypass perfusate taken from the heart‐lung machine for 20 patients who underwent cardiac surgery and were randomly divided into four groups according to the filters used. A leukocyte removal filter was installed in the transfusion line while the perfusate was transfused to the patients. No increases of C3a, C5a, elastase, and thromboxane were found during leukocyte filtration by polyester filters (Optima, Sepacell R500, and Pall RC100). Activation of the complement cascade was observed during filtration by the cellulose acetate filter (Cellselect) although the efficacy of the Cellselect filter was evidently higher than that of the poly‐ester filter. These results imply that polyester leukocyte filters are superior to cellulose acetate filters in terms of biocompatibility but have a reduced efficacy. An optimal leukocyte filter providing both high efficacy and biocompatibility has yet to be developed.
Pretransplantation Immunoadsorption Therapy in Patients Immunized with Human Lymphocyte Antigen: Effect of Treatment and Three Years' Clinical Follow‐up of Grafts
Authors: Alarabi Abdelmoniem Abdelmahmoud , Wikström Björn , Backman Ulla , Danielson Bo G. , Tufvesson Gunnar , Sjöberg Olof
Published: July 2010

Abstract: Sensitization against human lymphocyte antigen (HLA) occurs frequently in previously transplanted patients that lose a first cadaveric graft. To shorten their time on the waiting list and reduce the incidence of early rejection in such patients, we performed immunoadsorption therapy by a tryptophan column in 10 patients as an attempt to remove circulating antibodies prior to regrafting. Resynthesis of antibodies was suppressed with cyclophosphamide and prednisolone. Following the course of immunoadsorption therapy, the panel reactive antibodies (PRA) decreased by more than 50% from the pretreatment values. In the present study, 8 patients were transplanted with cadaveric renal grafts. At the time of follow‐up, graft survival was 63% in these patients (2–36 months post‐transplantation, mean 23 months). There was one incidence of acute rejection, one graft was lost within 48 h owing to renal artery thrombosis, and one was lost within 2 weeks as a result of stenosis. The serum creatinine levels were down to near normal during the first 3 weeks in hospital (p < 0.0001) and remained at this level during the period of follow‐up. We conclude that immunoadsorption might be a beneficial pretransplantation therapy and an alternative to plasmapheresis in HLA‐immunized patients awaiting kidney transplantation.
Continuous Hematocrit Monitoring Method in an Extracorporeal Circulation System and Its Application for Automatic Control of Blood Volume during Artificial Kidney Treatment
Authors: Ishihara Toshikazu , Igarashi Isemi , Kitano Tomoyuki , Shinzato Takahiro , Maeda Kenji
Published: July 2010

Abstract: A two‐frequency electrical conductivity method for measuring hematocrit has been developed for use in the continuous monitoring of circulating blood volume during artificial kidney treatment. Using this method, an algorithm for programmed control of blood volume also has been developed. This hematocrit measurement method is based on the β‐dispersion of blood conductivity, and the values measured during hemodialysis are in good agreement with the laboratory hematocrit values obtained by a Coulter counter. Programmed control of blood volume was used 29 times on 11 patients undergoing long‐term dialysis. In each case, the blood volume was maintained within 2.5% of the desired level, and stable control was achieved even with disturbances caused by eating, change in body position, and so on. These methods can be used to study the relationship between blood volume and dialysis‐induced hypotension during artificial kidney treatment and to achieve adequate ultrafiltration without clinical adverse effects.
Porcine Pancreatic Islets: Isolation, Microencapsulation, and Xenotransplantation
Authors: Sun Yi‐Lu , Ma Xiaojun , Zhou Daobiao , Vacek Ivan , Sun Anthony M.
Published: July 2010

Abstract: To provide a plentiful source of pancreatic islets for future clinical transplants into diabetic patients, we have developed a simple and reliable method to isolate porcine islets of a high degree of purity. Porcine pancreata were perfused and digested with collagenase, and the islets were then purified on dextran density gradients. In order to avoid any damage to the islets, no mechanical devices nor any strenuous treatment was employed. As many as 5 times 105 islets were isolated from a single porcine pancreas. Islets were encapsulated in alginate‐polylysine‐alginate membranes with the aid of an electrostatic droplet generator. In vitro studies demonstrated that the isolated islets secreted insulin in response to glucose and 3‐isobutyl‐L‐methylxanthine (IBMX) challenge for at least 4 weeks. Perifusion studies showed that the kinetics of insulin release from the encapsulated islets was similar to that exhibited by free islets. In in vivo studies, 18 diabetic BALB‐c mice were transplanted with 1,500‐2,500 encapsulated islets each. In 13 recipients, the diabetic condition was reversed for at least 85 days. When capsules were removed from 2 transplant recipients, their diabetic condition quickly recurred.
The Significance and Prevention of Air Emboli with the Total Artificial Heart
Authors: Murray Kevin D. , Binkley Philip F. , Durnond David A. , Watson Kim M. , Howanitz E. Paul , Ross Patrick , Myerowitz P. David
Published: July 2010

Abstract: Embolism remains a significant complication of the total artificial heart (TAH). The ineffectual deairing of the TAH can allow embolization of the retained air. The standard needle aspiration of TAH air (Group A) was compared with a new protocol (Group B) that included standard needle TAH aspiration plus simultaneous pumping of the TAH against an occluded ascending aorta and main pulmonary artery with vacuum applied to a needle in the proximal aorta and pulmonary artery. There were 4 calves in each group. There was no premortem evidence of systemic or pulmonary emboli. Both groups of animals were electively terminated less than 2 weeks postoperatively. Postoperative mean aortic and pulmonary artery pressures were recorded for each animal. Animals in Group B had a significant decline in pulmonary artery pressures (43 ± 12 vs. 33 ± 8 mm Hg) 1 h after TAH implantation when compared with Group A. All other aortic and pulmonary artery pressure differences between Groups A and B were not statistically significant within 24 h of the operation. Group A animals had a 75% incidence, and Group B animals had 100% incidence of TAH thrombus. This very small thrombus was found exclusively at the inflow valve‐TAH housing interface. Evaluation of the kidneys postmortem was used to identify embolic injury. All animals in Group A had evidence of acute, hemorrhagic injury, but none of the Group B animals had similar injury. Half of the animals in each group had small, fibrotic chronic renal cortical injury, which did not develop during TAH implantation. The more vigorous deairing protocol (Group B) significantly decreased early postoperative pulmonary hypertension. The absence of acute hemorrhagic renal injuries appeared to be associated with improved TAH deairing. Chronic renal injuries were not associated with the TAH, which makes them poor indicators of TAH emboli. Improved TAH deairing can provide beneficial effects for the recipient.