bluuebunny/crossref_metadata_2025 huggingface dataset:
Posttreatment with Amino Compounds Effective in Prevention of Calcification of Glutaraldehyde Treated Pericardium
Authors: Chanda Jyotirmay
Published: November 2008

Abstract: An attempt has been made to compare the role of different amino compounds in prevention of calcification of glutaraldehyde (GA)‐treated pericardium implanted subcutaneously in the rat for 12 weeks. GA pretreated pericardial samples were postfixed separately with glycine, albumin, gentamicin, glycine + gentamicin, and albumin + gentamicin. Severe calcification was noticed in animals undergoing albumin or gentamicin postfixation. Mild calcification was observed in glycine and albumin + gentamicin postfixed materials whereas calcium was undetectable either chemically or morphologically in GA‐pretreated pericardium postfixed with glycine + gentamicin (0.32 ± 0.13 mg/g calcium, dry wt; von Kossa 0) at the 12th week of implantation in the rat.
Cardiopulmonary Bypass with Nikkiso and BioMedicus Centrifugal Pumps
Authors: Orime Yukihiko , Takatani Setsuo , Sasaki Tatsuya , Aizawa Takeshi , Ohara Yasuhisa , Naito Kozo , Glueck Julie , Noon George P. , Nosé Yukihiko , DeBakey Michael E.
Published: November 2008

Abstract: In our department, a new compact and atraumatic centrifugal pump, Nikkiso, was developed as a second‐generation cardiopulmonary bypass pump. To assess and confirm the function and controllability of this pump, comparative studies of cardiopulmonary bypass with Nikkiso and BioMedicus centrifugal pumps were performed using calves. Both pumps provided pump flows of 60–70 ml/kg/min without incidence. The hemodynamics of both groups were stable and within the normal range, and no leakage or thrombus formations were observed in either pump. All hematology and biochemistry data showed no significant differences between the two groups. Plasma free hemoglobin values of the Nikkiso pump tended to be lower than those of the BioMedicus pump. The Nikkiso pump was easy to handle because of its smaller size, and air removal was easily performed because of its low priming volume. The Nikkiso pump demonstrated easy manipulation and good controllability. This compact, atraumatic centrifugal pump meets the requirements for a second‐generation cardiopulmonary by‐pass pump.
Flow Visualization in the Baylor Total Artificial Heart
Authors: Orime Yukihiko , Takatani Setsuo , Tasai Kimitaka , Ohara Yasuhisa , Naito Kozo , Mizuguchi Kazumi , Makinouchi Kenzo , Rosenow Sven E. , Glueck Julie , Nono George P. , DeBakey Michael E. , Nosé Yukihiko
Published: November 2008

Abstract: To analyze the flow patterns of the left and right blood chambers of the total artificial heart (TAH), flow visualization studies were performed. Two setup levels were used for the flow visualization studies. For estimating the global flow patterns, the pumps were illuminated using incandescent light, and the patterns were recorded by either videotape or photography. To evaluate sectional flow patterns, a laser light was applied, and the pump could be scanned segmentally. The flow patterns were recorded by a high‐speed camera. A signal was also used that synchronized the timing of the camera shutter to the pusher‐plate movement signal. In the left pump chamber, major stagnations were observed in the middle area of the inflow site. To solve this problem, a modification was made that changed the inflow direction appropriately. After evaluation of the inflow port direction, a proper flow pattern was obtained, which was validated by a global flow visualization study. Furthermore, both pump chambers indicated excellent flow patterns as obtained by a segmental flow visualization study method utilizing a laser light. The Baylor TAH demonstrated excellent flow patterns in flow visualization studies, with antithrombogenicity expected. These flow visualization studies are very useful not only for validations of global flow patterns but also for validations of local areas of stagnation in various blood pumps.
Comparative Study of Five Types of IABP Balloons in Terms of Incidence of Balloon Rupture and Other Complications: A Multi–Institutional Study
Authors: Nishida Hiroshi , Koyanagi Hitoshi , Abe Tomio , Arai Hirokuni , Hirayama Haruo , Hirayama Toitsu , Honda Takashi , Inoue Yasuo , Katsumata Takahiro , Kitamura Nobuo , Kumon Keiji , Nonoki Hiroshi , Sakamoto Tohru , Sone Takahito , Suzuki Shin , Tamai Hideo , Watanabe Sunao , Yoshioka Yukio
Published: November 2008

Abstract: The Multi–Institutional IABP Balloon Study Group in Japan (14 institutions) conducted a retrospective nonrandomized study to elucidate the incidence and type of IABP balloon–related complications relative to design and durability of five different clinically available balloons: TMP (n = 960), Kontron (n = 943). Datascope (n = 485), Mansfield (n = 226), and Aries (n = 189) balloons. A total of 2, 803 patients (1, 973 males, 830 females, mean age 62. 1 years) spent a total of 243, 856 h on the pump. Forty–nine balloons (1. 7%) ruptured as recognized by the appearance of blood in the catheter (39 cases) or console alarm (4 cases). Ten patients required surgical removal of the balloon due to entrapment. Other IABP balloon–related complications requiring surgical intervention or with a lethal outcome occurred in 89 patients (3. 2%). They included lower limb ischemia (61 cases), hematoma (11 cases), extensive dissection (6 cases), perforation (5 cases), entrapment without balloon rupture (3 cases), and mesenteric infarction (3 cases). The incidence of rupture, other major complications, and total complications, respectively, for each balloon was 0, 2. 7, and 2. 7 for TMP, 1. 6, 4. 3, and 5. 9% for Kontron, 4. 1, 1. 9, and 6. 0% for Datascope, 1. 3, 2. 7, and 4. 0% for Mansfield, and 5. 8, 3. 7, and 9. 5% for Aries. In conclusion, the TMP balloon demonstrates a significantly lower rate of rupture while the incidence of other complications for the 5 balloons is not significantly different.
Intravascular Membrane Oxygenation and Carbon Dioxide Removal with IVOX: Can Improved Design and Permissive Hypercapnia Achieve Adequate Respiratory Support During Severe Respiratory Failure?
Authors: ZWISCHENBERGER JOSEPH B. , JR VICTOR J. CARDENAS , TAO WEIKE , NIRANJAN S. C. , CLARK JOHN W. , BIDANI AKHIL
Published: November 2008

Abstract: The intravenacaval oxygenator and carbon dioxide removal device (IVOX) conceived by Mortensen at CardioPulmonics is a diffusion–limited device capable of removing 30% of CO2 production of an adult at normocapnia with minimal reduction in ventilator requirements. Through mathematical modeling, an ex vivo venovenous bypass circuit to model the vena cava and animal models of severe smoke inhalation injury, the practice of permissive hypercapnia has been established to enhance CO2 removal by IVOX. By allowing the blood PCO2 to rise gradually, the CO2 excretion by IVOX can be linearly increased in a 1: 1 relationship. Experimental and clinical studies have shown that CO2 removal by IVOX increased from 30–40 ml/min at normal blood PCO2 to 80–90 ml/min at PCO2 of 90 mm Hg. In addition, IVOX with permissive hypercapnia allowed a significant reduction in minute ventilation and peak airway pressure. Design changes could also improve the performance of IVOX. Increased surface area and mixing with more fibers and crimping in new prototypes of IVOX significantly increased CO2 removal and oxygen transfer. Active mixing in the blood to decrease the boundary layer resistance can further enhance gas exchange of IVOX. In conclusion, gas exchange by the current design of IVOX is limited, and improvements in design are needed for it to become a more clinically applicable device. Permissive hypercapnia can significantly enhance CO, removal by IVOX as well as significantly reduce ventilator requirements.
Review of Immunomodulation by Photopheresis: Treatment of Cutaneous T–Cell Lymphoma, Autoimmune Disease, and Allograft Rejection
Authors: WOLFE JONATHAN T. , LESSIN STUART R. , SINGH ANJALI H. , ROOK ALAIN H.
Published: November 2008

Abstract: Photopheresis is an apheresis–based therapy that is currently available at approximately 70 medical centers worldwide. Recent evidence indicates that extracorporeal photopheresis can significantly prolong life as well as induce a 60–75% response rate among individuals with advanced cutaneous T–cell lymphoma (CTCL). Moreover, a 10–15% cure rate, in response to photopheresis alone, or in combination with interferon–a, has been obtained at our institution. These complete responses have been characterized by the complete disappearance of morphologically atypical cells from the skin and blood. Southern blot analysis of peripheral blood specimens has also confirmed the indefinite disappearance of the malignant T–cell clone from the blood of patients with complete responses. Current immunological data obtained from in vitro human studies and from animal models suggest that the basis for the responses of CTCL patients are related to activation of treated macrophages resulting in release of cytokines, including substantial levels of tumor necrosis factor a (TNF‐α), and perhaps, to the induction of anticlonotypic immunity directed against pathogenic clones of T lymphocytes. In addition to the treatment of CTCL, a potential role for photopheresis in the therapy of autoimmune disease has been suggested by recent pilot studies of pemphigus vulgaris, rheumatoid arthritis, and systemic lupus erythematosus. Furthermore, a randomized, single–blinded trial involving 79 patients with early onset, aggressive systemic sclerosis suggested that photopheresis could beneficially affect the course of the cutaneous thickening in this form of the disease. Lastly, two independent pilot studies of cardiac transplantation have indicated that photopheresis can reverse acute cardiac allograft rejection and potentially suppress ongoing chronic rejection. Randomized, controlled trials for these new indications for photopheresis therapy are currently in the early stages of implementation.
Complement Activation by Alginate–Polylysine Microcapsules Used for Islet Transplantation
Authors: DARQUY SYLVIANE , PUEYO MARIA E. , CAPRON FREDERIQUE , REACH GERARD
Published: November 2008

Abstract: A foreign body reaction is frequently observed around implanted microcapsules of alginate–polylysine. Since complement activation can play a role in this reaction, we checked in vitro the ability of empty alginate–polylysine microcapsules to activate complement. Human serum was incubated with microcapsules, and complement activation was evaluated by two methods: the complement hemolytic activity (CH50) and the assay of the C3adesArg fragment. The occurrence of complement activation in the presence of microcapsules was suggested both by a CH50 decrease and by high C3adesArg levels despite C3adesArg adsorption to the capsule membrane. Capsule membrane protection against the cytotoxic effects of complement was also tested. No hemolysis occurred when microencapsulated sensitized sheep erythrocytes were incubated with activated complement. In conclusion, the microcapsule membrane can protect cells against activated complement fragments. Nevertheless, alginate–polylysine microcapsules do activate complement, and this effect must be considered for its use as an implant.
Experimental Assessment of Right Ventricular Function in Normal Pigs with a Left Ventricular Assist Device
Authors: KOTOH KEIJU , ISHII KOJI , ABE YOSHINOBU , DELEUZE PHILLIP , LOISANCE DANIEL
Published: November 2008

Abstract: Right ventricular (RV) failure during the use of a left ventricular assist device (LVAD) is the leading cause of death in circulatory support patients. Previous work, both experimentally and clinically, has shown the difficulties in predicting the behavior of the right ventricle at the start of LVAD. An experimental study has been designed to evaluate RV functional changes during LVAD and its relation to preload changes. The model used adult mongrel pigs (n = 10). Right ventricular functional parameters were measured with a thermodilution RV ejection fraction catheter. The left ventricle was supported by a Nippon Zeon blood pump. Two groups were studied, the first one was the LVAD–off group (n = 5) and the other was the LVAD–on group (n = 5) which was supported by LVAD at maximum flow. Change of cardiac output, mean pulmonary artery pressure (PAP), RV stroke work, and RV ejection fraction in both groups were not significantly different. However, the relationship between right ventricular end–diastolic pressure (RV–EDP) and right ventricular stroke volume (RVSV) was significantly changed at a high level of RV–EDP. When RV–EDP was over 6. 5 mm Hg in the LVAD–off group, RVSV decreased to 52. 3 ± 11. 5 ml while in the LVAD–on group, RVSV increased to 97. 2 ± 22. 0 ml. The change in PAP in the LVAD–on group was lower than in the LVAD–off group. We conclude that, at the volume overload state, LVAD can reduce the afterload of the right ventricle and maintain Frank–Starling's effect, thus having a beneficial effect on right ventricular performance.
Urinary Excretion of Thromboxane and Markers for Renal Injury in Patients Undergoing Cardiopulmonary Bypass
Authors: Jörres A. , Kordonouri Olga , Schiessler A. , Heβ Susanne , Farke S. , Gahl G. M. , Müller C. , Djurup R.
Published: November 2008

Abstract: Urinary excretion of selected markers for renal injury, as well as urinary excretion rates of the thromboxane metabolite, 11–keto–thromboxane B2 (llk–TXB2), was studied in 36 male patients undergoing coronary bypass surgery using cardiopulmonary bypass (CPB). In all patients, excretion of both tubular (AT–acetyl–(β–D–glucosaminidase [βNAG]; α1–microglobulin [α, –MG]) and glomerular markers (albumin [Alb]; transferrin [Trf]; immunoglobulin G [IgG]) sharply increased on Day 1 after CPB, and they remained elevated throughout the observation period of 5 days. Urinary excretion rates of 11k–TXB2 markedly increased on Day 1 after surgery, and they rapidly decreased thereafter. In 12 of the 36 patients, a temporary increase of serum creatinine levels (>1. 30 mg/dl) was noted following surgery. A positive correla tion was found between serum creatinine levels and excretion of the tubular enzyme βNAG (r = 0. 36; p < 0. 05), but not between creatinine levels and α1–MG or the glomerular markers. Furthermore, no correlation between urinary excretion of llk–TXB2 and any of the urinary markers for renal injury could be detected. Our data do not strengthen the hypothesis that acute renal injury observed during CPB is related to exaggerated thromboxane biosynthesis in these patients. Monitoring of urinary markers for incipient renal damage, particularly excretion of βNAG, might be of additional diagnostic value for detection of otherwise subclinical renal injury in patients undergoing CPB.
Do We Really Need Pulse? Chronic Nonpulsatile and Pulsatile Blood Flow: From the Exercise Response Viewpoints
Authors: Yozu R. , Golding L. , Yada I. , Harasaki H. , Takatani S. , Kawada S. , Nosé Y.
Published: November 2008

Abstract: The response of the body and the blood pump was evaluated in animals with a pulsatile artificial heart (total artificial heart [TAH]) and those with a nonpulsatile artificial heart (nonpulsatile biventricular bypass [NPBVB]) subjected to the same exercise load. The animals used in this study were 5 calves implanted with a pusher–plate type TAH (45–206 days) and 5 calves implanted with a nonpulsatile centrifugal pump (34–99 days). The pre–exercise pump flow rate was 92. 1 ± 8. 1 ml/kg/min for the TAH group and 94. 8 ± 9. 1 ml/kg/min for the NPBVB group, with no significant difference between the two groups. The workload was administered at a rate of 1. 5 mph for 15 min. The artificial heart driving conditions were kept constant throughout the test period. Sequential changes in hemodynamic response and metabolism were determined before, during, and for 30 min after exercise. Both TAH and NPBVB calves showed excellent tolerance of the workload (1. 5 mph exercise); in NPBVB calves, oxygen demand was compensated for by an increase in the arteriovenous oxygen difference during exercise; and norepinephrine showed a greater response in the NPBVB group. Based on the results presented, the nonpulsatile pump seems to lend itself to a mechanically driven artificial heart of the complete implantation type because of its small size, high efficiency, and the lack of need for a compliance chamber.
Does Hematocrit Affect In Vitro Hemolysis Test Results? Preliminary Study with Baylor/NASA Prototype Axial Flow Pump
Authors: Mizuguchi Kazumi , Damm George A. , Aber Greg S. , Bozeman Richard J. , Bacak Jim W. , Svejkovsky Paul A. , Orime Yukihiko , Ohara Yasuhisa , Naito Kozo , Tasai Kimitaka , Makinouchi Kenzo , Takatani Setsuo , Nosé Yukihiko , Noon George P. , DeBakey Michael E.
Published: November 2008

Abstract: The effect of hematocrit (Ht) on in vitro hemolysis test results (i. e., index of hemolysis) was evaluated using a Baylor/NASA prototype axial flow pump. Red blood cell suspensions of six different Ht (5, 10, 15, 20, 30, 40%; n = 30) were prepared and used for this evaluation. The pump was operated for 60 min under 5 L/min flow conditions, and blood samples were taken every 10 min to measure plasma free hemoglobin levels. The normalized index of hemolysis (NIH) was calculated using the regression line slope between time and plasma free hemoglobin level, and relationships between NIH and Ht or hemoglobin (Hb) were checked. NIH and Ht had a statistically significant (p < 0.0001) correlation with a coefficient of fit of 0.976, and NIH and Hb had a statistically significant (p < 0.0001) correlation with a coefficient of fit of 0.976. To reduce the effect of Ht, NIH/Ht was pro posed and compared with a modified index of hemolysis (MIH), which was normalized by the Hb level of blood. NIH/Ht and MIH had a poor correlation with Ht (coefficient of fit, 0.608) and Hb (coefficient of fit, 0.577), respectively. When blood that has a wide range of Ht or Hb values is used for in vitro hemolysis tests, NIH/Ht is suggested for use as an index of hemolysis to evaluate the hemolysis characteristics of rotary blood pumps because MIH has no dimension and it requires Hb values. In contrast, NIH/Ht has a dimension of g/100 L, which is quite understandable, and it does not require measurement of Hb levels of blood; it is therefore cost–effective.
Transplantation of Autologous Tissue Fragments into an e‐PTFE Graft with Long Fibrils
Authors: Noishiki Yasuharu , Yamane Yoshihisa , Tomizawa Yasuko , Matsumoto Akihiko
Published: November 2008

Abstract: An expanded polytetrafluoroethylene (e‐PTFE) graft with long fibrils transplanted with bone marrow showed rapid and uniform neointima formation in a dog study. The e‐PTFE grafts (fibril length, 90 μm; 6 mm internal diameter; length, 6–8 cm) transplanted with autologous bone marrow were implanted in the abdominal aortae of 10 dogs and retrieved at 3 weeks and 3 months after implantation. Control e‐PTFE grafts without bone marrow treatment were also implanted in the same manner in 8 dogs. Macroscopically the treated graft wall appeared red in color; however, there was no thrombus deposition on the surface. Light microscopic observation revealed that the treated grafts were completely lined with endothelial cells at 3 weeks. The neointima was uniform without intimai hyperplasia at the anastomotic sites.

Inside the graft wall many capillary blood vessels were observed. At 3 months moderate intimai hyperplasia throughout the graft with complete endothelialization was observed. In the control grafts, endothelialization was observed at the anastomotic sites; however, half of the other areas were covered with a fibrin layer devoid of endothelial cells even in the 3‐month grafts. These results indicated that neointima formation was effectively accelerated with the autologous bone marrow transplantation, but moderate intimai hyperplasia throughout the graft was inevitable in e‐PTFE grafts even after complete endothelialization.
A New Cardiac Wall Substitute Made of Dacron Fabric Prosthesis Sealed with Autologous Tissue Fragments: Comparative Studies of Neointima Formation and Bleeding Resistant Property Against Fibrinolysis Phenomenon with Those of a Preclotted Sealing Graft
Authors: Kajiwara Hirokazu
Published: November 2008

Abstract: A cardiac wall substitute made of a Dacron fabric prosthesis sealed with minced autologous tissue fragments was developed. An animal study showed rapid neointima formation on the graft luminal surface and no bleeding problem under load test with tissue plasminogen activator (tPA) administration. To evaluate the efficacy of the sealing method, a special substitute that was sealed with tissue fragments in one half and preclotted with fresh blood in the other half was prepared. The grafts were implanted into the right ventricular outflow tract in 14 dogs. During a load test with administration of tPA intravenously, the preclotted area bled quite remarkably; however, the area sealed with tissue fragments did not bleed. Two weeks after implantation, red thrombus adhered on the preclotted area, while a white, glistening surface was noticed on the tissue fragments area. Light microscopical observation showed complete neointima formation in the tissue fragmented area but a thrombus layer in the preclotted area. These results indicated that the tissue fragmentation was a superior method compared with preclotting for creating a cardiac wall substitute.
The Beneficial Effect of Low Initial Dose and Gradual Increase of Erythropoietin Treatment in Hemodialysis Patients
Authors: Walter Judit , Gål Jözsef , Taraba István
Published: November 2008

Abstract: It is well known that the effects of human re‐combinant erythropoietin (rHuEPO) are dose‐dependent. However, when higher doses of rHuEPO are used, the frequency of the side effects also increases. The aim of our study was to analyze the hematologic parameters and blood pressure response in hemodialysis patients treated with low initial and gradually increased rHuEPO. Sixteen regular hemodialysis patients were treated with 3 times 20 U/kg/week of rHuEPO subcutaneously during the first month. Every fourth week the dose was increased by 3 times 20 U/kg/week if the hematocrit did not rise by 2%. If the elevation was 2% or more, the dose of the rHuEPO was not changed. Blood count and blood pressure were checked every week. The antihypertensive treatment was also reviewed weekly. The hematocrit increased significantly from the second week, and 11 patients achieved the target level (30%) between Weeks 8 and 24. Two patients reached the 30% hematocrit level between Weeks 2 and 8, and another 2 patients reached the target level between Weeks 25 and 28. There was 1 nonresponder. The average rHuEPO dose needed to achieve the target hematocrit was 56.3 U/kg/week. We did not observe significant changes in the mean arterial or diastolic blood pressure. It was necessary to increase the doses of anti‐hypertensive drugs, namely nifedipine and captopril, to control blood pressure. Encephalopathy occurred in none of the cases. The low initial dose and the gradual increase of rHuEPO treatment were beneficial to the hemodialysis patients. Although the target hematocrit took longer to achieve, high blood pressure and encephalopathy were prevented by close monitoring and administration of suitable antihypertensive treatment.
In Vitro Binding of Radiocesium to Prussian Blue Coated Strips and Prussian Blue Containing Hemoperfusion Columns as a Potential Tool for the Treatment of Persons Internally Contaminated with Radiocesium
Authors: Verzijl J.M. , Wierckx F.C.J. , van Dijk A. , Gleru J.H.
Published: November 2008

Abstract: Cellulose or nylon strips coated with three different Prussian Blue salts were prepared with cellulose nitrate as binding material. These strips were evaluated for their usefulness for the development of an extracor‐poral clearance device for radiocesium, a radionuclide often released after accidents in nuclear installations (for example in Chernobyl). Extracorporeal clearance can be used to enhance the elimination of radiocesium from internally contaminated persons. The stability of these strips and their binding characteristics for radiocesium were investigated. In all studies strips coated with Fe4[Fe(CN)6]3 proved to be the most suitable for further development of an extracorporal clearance device: the strips are stable, have a high binding capacity for radiocesium, and can be sterilized. On the basis of these results, hemoperfusion columns containing Fe4[Fe(CN)6]3‐coated strips were developed and tested. In in vitro experiments these columns proved to be successful in removing radiocesium from a pasteurized plasma solution (clearance was ˜ 100 ml/min). The binding capacity of these columns is relatively high. In 4 h the columns are able to bind ˜0.3 TBq of radiocesium. They are a promising development for the enhancement of the removal of radiocesium from the human body. They can also be used for the decontamination of other fluids of chemical or biological origin. Further research is, however, still necessary.
Double Filtration Plasmapheresis Enhances Neutrophil Chemotactic Responses in Hyperimmunoglobulin E Syndrome
Authors: Yamada Hiromichi , Nagaoka Isao , Takamori Kenji , Ogawa Hideoki
Published: November 2008

Abstract: The patient, a 32‐year‐old male, was diagnosed as having hyperimmunoglobulin E syndrome and was subsequently treated with double filtration plasmapheresis (DFPP). The patient showed a defective chemotaxis with reference to polymorphonuclear leukocytes and the presence of chemotactic inhibitor in his serum. By the fifth treatment with DFPP, chemotactic responses had improved, and there was no further evidence of chemotactic inhibitor in his serum. These findings suggest that the patient's chemotactic responses improved as a result of the removal or decrease in chemotactic inhibitor in his serum upon treatment with DFPP. Accordingly DFPP may be an effective treatment for hyperimmunoglobulin E syndrome.
Middle Molecules: Toxicity and Removal by Hemodialysis and Related Strategies
Authors: Vanholder Raymond , De Smet Rita , Vogeleere Pascale , Ringoir Severin
Published: November 2008

Abstract: Renal failure results in the retention of metabolites which may arbitrarily be grouped according to their molecular weight: low (<300 daltons molecular weight), middle (300–15, 000 daltons), and high (> 15, 000 daltons). Opinion in respect to the relative importance of these groups varies. Initially it was thought that small molecules were important. In the mid‐1970s, investigators identified the possible pathophysiological role of middle molecules. However, since positive identification of such molecules was difficult, opinion has shifted back in favor of small molecules, and little attention, with the exception of β2 microglobulin, has been paid to middle molecules and their removal by hemodialysis and related therapies. In this review current knowledge regarding middle molecules identified as uremic toxins and their removal by hemodialysis and associated therapies are discussed.
Long‐Term Follow‐up of 6–8 mm Brachioaxillary Polytetrafluorethylene Grafts for Hemodialysis
Authors: Polo José R. , Tejedor Alberto , Polo Jorge , Sanabia Juan , Calleja Javier , Gómez Francisco
Published: November 2008

Abstract: Eight millimeter expanded polytetrafluoroeth‐ylene (e‐PTFE) grafts, tapered to 6 mm at the arterial site, are used by our group in the upper arm in order to avoid midgraft stenosis observed with other graft sizes. Long‐term results (1–12 years) on 157 6–8 mm brachioaxillary e‐PTFE grafts (Gore‐Tex) are analyzed. Early failure was found in 4 grafts (2.5%). The rate of late complications was 0.37 episodes per graft‐year. Steal syndrome, found in 4 cases (2.5%), was successfully treated in 3 cases by graft banding. Neither midgraft nor arterial anastomotic stenosis was observed in the 63 grafts requiring surgical thrombectomy or fistulography. The primary patency rates were 73%, 53%, and 41% at 1, 3, and 5 years, respectively. The secondary patency rates were 91%, 80%, and 72% at 1, 3, and 5 years, respectively. Comparison between both curves by the log rank test was significant (p < 0.001) expressing the efficiency of rescue surgery. We conclude that a 6–8 mm graft can be successfully used for dialysis in the brachioaxillary position
Effects of Recombinant Human Erythropoietin and Exercise Training on Exercise Capacity in Hemodialysis Patients
Authors: Akiba Takashi , Matsui Noriaki , Shinohara Shinsuke , Fujiwara Hideomi , Nomura Takeo , Marumo Fumiaki
Published: November 2008

Abstract: The effects of recombinant human erythropoietin (rHuEPO) and exercise training on exercise capacity were evaluated in 20 hemodialysis patients. After improvement of anemia by rHuEPO (Phase I), patients were divided into 2 groups. Group 1, 10 patients, was placed in a 3–month exercise training program. Group 2, 10 patients, served as a control group (Phase 2). A symptom‐limited exercise tolerance test was performed at the start of Phase 1 and before and after Phase 2. Hemoglobin (Hb) values were kept constant throughout Phase 2. In Phase 1, maximum workloads (62.0 ± 19.1 to 76.5 ± 25.6 W, p < 0.001), maximum O2 uptake (Vo2max) (18.7 ± 3.5 to 2.2 ± 5.9 ml/min/kg, p < 0.01), and Vo2 at anaerobic threshold (AT) (Vo2AT) (8.5 ± 2.1 to 10.2 ± 2.9 ml/min/kg, p < 0.01) were all improved by rHuEPO. However, in Phase 2, despite unchanged Hb values and maximum workloads, Vo2max (20.7 ± 4.6 to 17.6 ± 2.6 ml/min/kg, p < 0.05) and Vo2AT (10.6 ± 1.4 to 9.5 ± 1.8, ml/min/kg p < 0.05) were decreased in Group 2. However, in Group 1, maximum workloads (66.7 ± 8.2 to 81.7 ± 7.5 W, p < 0.01) were improved, and Vo2max and Vo2AT were not decreased significantly in the same period. Exercise training in rHuEPO‐treated hemodialysis patients resulted in an improved aerobic exercise capacity, whereas those without exercise training did not have increased capacity. Throughout the study, O2 uptakes were lower than those of nonrenal anemic patients who had similar Hb values. Maximum lactate values also remained low. In conclusion, improvement in the exercise capacity in hemodialysis patients treated with rHuEPO was minimal. Some defects were suggested in the aerobic energy production system in skeletal muscle of dialysis patients. Anemia‐improved patients should participate in incremental physical activity to maintain an improved exercise capacity.
An In Vitro Evaluation of Venous Cannula in a Simulated Partial (Femoro‐Femoral) Cardiopulmonary Bypass Circuit
Authors: Kugai Tadao , Koja Kageharu , Kusaba Akira
Published: November 2008

Abstract: We designed a study to evaluate three factors (siphon gradient [PH], the right atrial pressure [RAP], and the inferior vena caval flow [IVCF]) to be optimized to maximize the venous drainage flow (DF) during partial cardiopulmonary bypass using eight venous cannulas of three different types and an original model circuit. The relationship between venous DF and the three factors is indicated by the multiple regression equation DF2= a PH +βRAP +γIVCF2+ C, where α, β, and γ are regression estimates and C is a constant. Multiple regression analysis results showed that DF was positively correlated with PH and RAP and negatively correlated with IVCF. A long cannula with 12 side holes and 60 cm long was considered to be useful to yield the optimal venous drainage flow under the condition of maintenance of the flow balance (DF and ICVF) and the pressure balance (RAP and IVCP) at the zero point. Moreover, this model may allow extensive research in flow dynamics of venous cannula without involving human subjects.
Electrotactile Stimulator for Artificial Proprioception
Authors: Nohama Percy , Lopes Andréa Vizzotto , Cliquet Alberto
Published: November 2008

Abstract: With the goal of investigating artificial proprioception elicited by electrical stimulation, we have developed a tactile phi phenomenon‐based stimulator. This two‐channel microprocessed pulse amplitude modulation system generates two different envelope waveforms (triangular and elliptical) and allows programming and visualizing of its main parameters: pulse width (0.1–10 ms), pulse frequency (0.1–10 kHz), modulation frequency (0.3–10 Hz), current intensity (up to 20 mA), and the amplitude modulation index (0–100%). In vivo experiments with 5 normal persons have shown that it is possible to elicit a moving fused phantom image with good resolution. A triangular envelope is good for straight line sensations while the elliptical one is more comfortable and has better resolution for all kinds of moving images.
Computational Prediction of Hemolysis in a Centrifugal Ventricular Assist Device
Authors: Pinotti Marcos , Rosa Eugenio S.
Published: November 2008

Abstract: This paper describes the use of computational fluid dynamics (CFD) to predict numerically the hemolysis in centrifugal pumps. A numerical hydrodynamical model, based on the full Navier‐Stokes equation, was used to obtain the flow in a vaneless centrifugal pump (of corotating disks type). After proper postprocessing, critical zones in the channel were identified by means of two‐dimensional color‐coded maps of %Hb release. Simulation of different conditions revealed that flow behavior at the entrance region of the channel is the main cause of blood trauma in such devices. A useful feature resulting from the CFD simulation is the visualization of critical flow zones that are impossible to determine experimentally with in vitro hemolysis tests.
Considerations on Developmental Aspects of Biocompatible Dialysis Membranes
Authors: Vienken J. , Diamantoglou M. , Hahn C. , Kamusewitz H. , Paul D.
Published: November 2008

Abstract: Modern strategies in developing new polymers for dialysis membranes aim to improve their blood compatibility. To achieve such a goal, two approaches have been successfully applied: existing cellulosic polymers were modified, either by introducing functional groups through ester or ether bonds, by mixing synthetic polymers with bulk additives, or by using copolymerization techniques. As a detailed example, the first synthetically modified cellulose membrane, Hemophan, was prepared by substituting some hydrogen atoms in the cellulosic glucose unit by diethyl‐amino‐ethyl groups with the modification having a considerable impact on the membrane's hemocompatibility. It is further known that the hemo‐compatibility of hydrophobic synthetic membranes is improved by rendering these materials partially hydrophilic. We tested the hypothesis, whether the hemocompatibility of a material, which is hydrophilic per se, such as unmodified cellulose, is changed after the introduction of hydro‐phobic substituents. For this purpose, the number and nature of substituents have been systematically varied in order to alter surface properties, and these variations have been subsequently related to blood compatibility parameters. As expected, thrombin generation as well as complement‐ and cell‐activation depend on the number and nature of the substituents whereby some of the substituents show a very narrow optimum if their hemocompatibility is related to the degree of substitution. Changes in hemocompatibility can be followed by physical methods, such as surface angle analyses and zeta potential determinations. Data show that alterations in the li‐pophilic/hydrophilic balance on the polymer surface may explain substituent‐related changes in polymer hemocompatibility. Molecular modeling of membrane surface and protein structures may be of further help in understanding possible interactions. The recent conclusion is that polymer modification and techniques in membrane surface characterization help us to optimize membrane fabrication for specific applications.
Function of Endocrine Organs in Hemodialyzed Patients of Long‐Term Erythropoietin Therapy
Authors: Kokto Franciszek , Wiȩcek Andrzej , Schmidt‐Gayk Heinrich , Marcinkowski Wojciech , Gilge Ullrich , Heidland August , Rudka Roman , Trembecki Jerzy
Published: November 2008

Abstract: Endocrine abnormalities in patients with chronic renal failure are well documented. The present study aimed to assess the influence of long‐term erythropoietin (EPO) therapy on endocrine abnormalities in hemodialyzed patients. Two groups of hemodialyzed patients, each of which comprised 17 subjects, were examined. The first group was treated by EPO (EPO group) while the second one did not receive this hormone (No‐EPO group). A complete biochemical and hormonal check‐up was performed before and at the 3, 6, 9, and 12 month points of the study period. Normal values for the estimated parameters were obtained in appropriately selected sex‐ and age‐matched healthy subjects. After EPO therapy, an increase of the hematocrit value from 21.8 ± 0.9 to 32.6 ± 0.9% was observed, which was accompanied by a significant decline of plasma ferritin and saturation of transferrin. In patients of the No‐EPO group, a significant although less marked rise of the hematocrit value (21.4 ± 0.4 to 24.2 ± 0.6%) was also noticed. EPO therapy did not change plasma levels of electrolytes (Na, K, Ca, inorganic phosphate), osteocalcin, creatinine, glucose, and alkaline phosphatase as well as plasma concentrations of calcium‐related hormones (PTH, calcitonin, 1,25[OH]2D3), vasopressin, and triiodothyronine. EPO treatment induced a significant decrease in somatotropin, prolactin, follitropin, lutropin, ACTH, cortisol, plasma renin activity, aldosterone, noradrenaline, adrenaline, dopamine, glucagon, pancreatic polypeptide, and gastrin plasma levels and an increase in plasma insulin, estradiol, testosterone, atrial natriuretic peptide, thyrotropin, and thyroxine. These EPO‐induced endocrine alterations were restricted mostly to the first 6 months of EPO administration. In patients of the No‐EPO group, a significant decrease in the plasma levels of prolactin, noradrenaline, and dopamine and an increase of estradiol plasma levels were also noticed during the 1‐year study period. Therefore, long‐term treatment by EPO shows profound effects on the function of several endocrine organs. These effects are transitory and predominantly restricted to the first 6 months of EPO therapy. Not all endocrine alterations observed in EPO‐treated patients seem to be due to the administration of this hormone.
Lipid Peroxidation and Vitamin E in Red Blood Cells and Plasma in Hemodialysis Patients Under rhEPO Treatment
Authors: Nenov D. , Paskalev D. , Yankova T. , Tchankova P.
Published: November 2008

Abstract: Lipid peroxidation, measured by malonyldial‐dehyde (MDA) and vitamin E in red blood cells (RBC) and plasma, was investigated in 25 hemodialysis (HD) patients before and after 6 months rhEPO therapy. RBC‐MDA was significantly elevated, but plasma MDA was in the reference range. After recombinant human erythro‐poietin (rhEPO) treatment, the MDA level was significantly decreased in both compartments. Marked vitamin E deficiency was established in RBC as well as in plasma. rhEPO therapy restored vitamin E levels in both compartments. Our data suggest a possible positive rhEPO‐antioxidant effect in HD patients.
Development of Immunosorbents for apoB‐Containing Lipoproteins Apheresis
Authors: Pokrovsky Sergei N. , Sussekov Andrey V. , Adamova Irina Y. , Afanasieva Olga I. , Benevolenskaya Galina F. , Konovalov Gennady A. , Kukharchuk Valery V.
Published: November 2008

Abstract: Three types of sorbents were developed for the specific removal of atherogenic apoB‐containing low‐density lipoprotein (LDL) and lipoprotein LDL(a) (Lp[a])from human plasma. Two sorbents contained monospecific sheep polyclonal or mouse monoclonal antibodies against human apoprotein B‐100. The third one was intended for specific removal of Lp(a) and contains sheep antibodies against human Lp(a). Thirty patients were treated for up to 9 years by LDL apheresis with anti‐LDL immunosorbents. A pilot study of Lp(a) apheresis with 3 patients was conducted during 3 years. The results showed that extracorporeal immunosorption is safe and effective for lowering LDL and Lp(a). These procedures may be used both for metabolic investigations and for studies on possible regression of atherosclerosis.
Cannula Selection and Cannulation Techniques for Nonpulsatile Mechanical Ventricular Assistance
Authors: Richenbacher Wayne E. , Marks John D.
Published: November 2008

Abstract: The successful use of mechanical ventricular assistance is, in large part, dependent upon easy insertion of well designed inflow and outflow cannulas. This manuscript describes a family of cannulas specifically designed for use in a nonpulsatile ventricular assist device (VAD) circuit. Although a variety of commercially available cannulas can be employed in a nonpulsatile VAD circuit, the cannulas described in this manuscript possess a number of unique design features. The reinforced thin‐walled design and end hole construction optimize fluid flow characteristics in both the inflow and outflow cannula. The extended length allows the cannulas to transverse the skin at a point far distant from the mediastinum, reducing the potential for ascending cannula site infection. The purpose of this manuscript is not to review all cannulas available for nonpulsatile VAD circuits, but rather to describe in detail a family of cannulas that are ideal VAD cannulas based on their design characteristics. In addition individual cardiac surgeons implant very few of these devices annually. Thus the advantages and disadvantages of common cannulation sites and a proven technique for cannula insertion will also be presented.
Constructional and Functional Characteristics of Recent Total Artificial Heart Models TNS Brno VII, VIII, and IX
Authors: Vašků Jaromír , Urbánek Petr
Published: November 2008

Abstract: Twelve total artificial heart (TAH) models have been developed at the Brno Research Center. Devices VII, VIII, and IX were constructed on the principle of asymmetry. Three main objectives had to be fulfilled by this construction. First, contact of the flap inflow valve with the diaphragm during the pumping cycle had to be avoided. Second, the evacuation regimen of the blood chamber needed to be improved. Third, the danger of thrombi formation due to the lesser incidence of the dead corners had to be decreased or eliminated. The type VII heart has a roof‐shaped polyurethane valve in the outflow tract whereas the type VIII heart has a flap valve. The decrease of thrombi incidence around the outflow valve was thus secured, and the driving pressure was decreased as well. In the type IX heart, the small additional flap valve is attached to the outflow valve. In one Brno VII device, Imachi's jellyfish valve has been mounted. Altogether, 62 long‐term experiments with survival times of 30–314 days have been performed. To this number, 4 comparative experiments using the Rostock artificial heart were added.
Computational Flow Optimization of Rotary Blood Pump Components
Authors: Antaki James F. , Ghattas Omar , Burgreen Greg W. , He Beichang
Published: November 2008

Abstract: In an effort to improve and automate the fluid dynamic design of rotary blood pumps, a coupled computational fluid dynamics (CFD) shape optimization methodology has been developed and implemented. This program couples a finite element flow simulation with a gradient‐based optimization routine to modify automatically the shape of an initial candidate blood path, according to a variety of desired fluid dynamic criteria, including shear stress, vorticity/circulation, and viscous dissipation. Preliminary results have led to both intuitive and nonintuitive transformations of the initial blood flow paths for both internal and external flows. This application of computer design optimization offers the ability to explore a much broader design space much more efficiently than would be possible with traditional parametric methods. It is believed that this computer tool can assist developers of rotary blood pumps in designing blood‐wetted components that minimize thrombosis and hemo‐lysis while simultaneously providing maximum flow performance.
Recent Studies of the Centrifugal Blood Pump with a Magnetically Suspended Impeller
Authors: Akamatsu Teruaki , Tsukiya Tomonori , Nishimura Kazunobu , Park Chang‐Hee , Nakazeki Tsugito
Published: November 2008

Abstract: We have been developing a centrifugal blood pump with a magnetically suspended impeller. To improve pump efficiency, we investigated the pump performances of many kinds of impeller vanes and diffusers, as well as the flow in the gap between the impeller discs and the pump housing. We found the vanes and the diffusers with high pump efficiency; however, high efficiency does not mean low hemolysis. It seems important to prevent generation of small‐sized eddies with high shear stress. Hemolysis tests are carried out to find the optimal vane profile and gap clearance. The index of hemolysis and temperature change of our pump is better than those of the Biopump. Short‐term in vivo studies show that the layer of white thrombi adheres to the machined rough surface of polycarbonate, which composes the narrow gap (0.2 mm) between the impeller and the pump wall, but a smooth surface coated with silicon prevents adhesion of that layer.
Initial Clinical Experience with the Baylor‐Nikkiso Centrifugal Pump
Authors: Ohtsubo Satoshi , Naito Kozo , Matsuura Motonori , Kawahito Koji , Shimono Takatsugu , Makinouchi Kenzo , Tasai Kimitaka , Ohara Yasuhiro , Damm George , Glueck Julie , Raskin Steven , Takatani Setsuo , Benkowski Robert , Short David H. , Schinen Scott A. , Noon George P. , Nosé Yukihiko
Published: November 2008

Abstract: Recently, a newly developed centrifugal pump, the Baylor‐Nikkiso pump, was approved for clinical use in the United States. This pump is the most compact centrifugal pump with a priming volume of only 25 ml. Although it is small, this pump can provide a flow of 4 L/min against a total pressure head of 300 mm Hg at 3,000 rpm. In vitro and in vivo validation of the Baylor‐Nikkiso pump has proved that this pump could effectively reduce blood trauma even under high total head pressure. In addition, 48‐h durability tests with biventricular bypass using calves verified the reliability of shaft sealing and anti‐thrombogenicity. Clinical trials of the Baylor‐Nikkiso pumps have been initiated in our department. This pump provides flows of 60–70 ml/kg/min with stable hemody‐namic conditions. No leakage or thrombus formation was observed. The results of the initial clinical experience of the Baylor‐Nikkiso pump suggest that it is suitable for cardiopulmonary bypass surgery.