bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer Simulation of Field Distribution and Excitation of Denervated Muscle Fibers Caused by Surface Electrodes
Authors: Reichel Martin , Mayr Winfried , Rattay Frank
Published: March 2003

In the course of this study, 2 submodels have been developed and combined, the 2‐D finite element modeling of the electrical potential distribution in the human thigh and a Hodgkin and Huxley (HH) type model to calculate fiber excitation and action potential propagation. To determine the excitation of the target muscle fiber with the help of the activating function, the fiber's orientation within the muscle has to be known. The electric field along the fiber has to be calculated as a function of the applied electric current and the potential at the electrodes, respectively. The excitement of the muscle fibers varies across a wide range depending on the active and passive membrane parameters and the intracellular and extracellular mediums. Persisting denervation leads to a decay of muscle cells, and a partial substitution by fibroblasts occurs. The electrical activation of these tissues is more difficult, and biphasic stimulation pulses up to 200 ms in duration and 60–100 V in amplitude are needed to cause a contraction of the denervated muscle. An example shows the field distribution and the simulated activity in one representative muscle fiber of a well trained m. rectus femoris.
Computational Simulation of Flows in an Entire Centrifugal Heart Pump
Authors: Nakamura Shoichiro , Yano Keiji
Published: March 2003

A prototype computational code to numerically simulate the blood flows in an entire centrifugal heart pump has been developed. The unsteady incompressible Navier‐Stokes equations are solved on a parallel computer, the Cray T3E. By domain decomposition, the whole flow space is decomposed to a number of subdomains for each of which a structured algebraic grid is assigned. The grids for the inlet eye and blade regions are on the rotating frame while grids for other regions are on the nonrotating frame, and the edge of the rotating grids slides over the edge of the nonrotating frame, and the edge of the rotating grids slides over the edge of the nonrotating grids. The code is able to simulate the flows in the rotor, volute, and diffuser as well as to find pump performance indicators. The present paper presents an overview of the code and describes a study on the effect of volute width.
Extracorporeal Membrane Oxygenation Discontinuation Despite Technically Successful Reoperation: A Case Report
Authors: Taferner Rainer , Golej Johann , Marx Manfred , Trittenwein Gerhard
Published: March 2003

Abstract: Death remains a probable outcome of pediatric cardiac extracorporeal membrane oxygenation (ECMO) despite increasing efforts to improve the results. On venoarterial ECMO, in an obviously hopeless situation, the decision to withdraw a life supporting measure resulting in the sudden death of a child places a heavy burden on the team. After valvulotomy of critical aortic stenosis in a prenatally diagnosed term neonate, ECMO had to be installed during postoperative resuscitation. Despite technically successful homograft implantation while on ECMO complicated by postoperative bleeding, advancing multiorgan failure resulted in ECMO withdrawal. As shown in this case report, exact termination criteria are lacking but are necessary to prevent increasing team and resource related conflicts in pediatric cardiac ECMO.
Five‐Year Follow‐Up of Valve Replacement with the Jyros Bileaflet Mechanical Valve
Authors: Onoda Koji , Yasuda Fuyuhiko , Komada Takuya , Pagoada‐Cruz Bayardo , Katayama Yoshihiko , Shimono Takatsugu , Shimpo Hideto , Yada Isao
Published: March 2003

Abstract: Jyros bileaflet rotating valves were implanted as a clinical trial conducted in Japan, and the 5‐year results were assessed. Nineteen patients underwent implantation of the valves: 14 in the mitral and 5 in the aortic position. The mean follow‐up period was 65.4 ± 15.7 months. There was 1 case of late death due to fatal arrhythmia and another case of cerebral thromboembolism (1.0% per patient year). All survivors were in New York Heart Association class I. On the early postoperative cinefluorography, 8 valves (42.1%) showed rotation of the leaflets. However, in the latest assessment 6 valves (33.3%) showed rotation, some valves had stopped rotation, and others had started to rotate during the follow‐up period. The Jyros valve functions effectively, similar to other bileaflet valves. However, because the correlation between thromboembolism and the rotation mechanism is not clear, further follow‐up of our patients and more implant studies are necessary to elucidate this issue.
Is Vecuronium Toxicity Abolished by Hemodialysis? A Case Report
Authors: Rollino Cristiana , Visetti Enrico , Borsa Simona , Pignataro Angelo , Pozzato Marco , Vallero Antonella , Quarello Francesco
Published: March 2003

Abstract: Vecuronium is a curaric agent, largely used in anesthesia. Indications as to its employ in uremic patients appear to be debated because of partial renal elimination of the drug. A 52‐year‐old hemodialyzed woman required transplantectomy for rejection. At awakeness after general anesthesia (induced with fentanyl, propofol, and 6 mg of vecuronium, repeated with a single 2 mg dose 30 min later), she presented diafragmatic and muscular limb weakeness that lasted 180 min in spite of prostigmine administration. A 2 h 30 min predilutional hemofiltration was then performed, which induced rapid disappearance of neuromuscular blockade. Even if vecuronium can be used in dialysis patients, one should remember its possible side effects, especially with repeated doses, in determining prolonged neuromuscular blockade. Cautious use of this drug in renal failure is mandatory. Low dosage must be employed and repeated administration avoided. Neuromuscular blockade seems to be rapidly reversible with dialytic treatment.
Preparation of Bioabsorbable Nerve Guide Tubes
Authors: Luciano Rubens M. , De Carvalho Zavaglia Cecília A. , De Rezende Duek Eliana Aparecida
Published: March 2003

Abstract: The use of bioabsorbable polymers in applications as temporary structural function, recovering damage in live tissues, is a promising research area. Membranes of poly(lactic acid) (PLA) may act as support to adhesion and cellular invasion or as devices for guided tissue regeneration (GTR). In this study, the same casting technique used to prepare membranes was used to prepare PLA tubes. These tubes can be used for tests in nerve guided regeneration (NGR). To improve flexibility of the device, a bioabsorbable plasticizer was added to the polymer. The initial results showed that the proposed technique allowed the preparation of flexible tubes that can be used for NGR.
Comparative Blood Flow Study of Arteriovenous Fistulae in Canine Femoral Arteries: Modified Latero‐Lateral and End‐Lateral Techniques
Authors: Galego Sidnei José , Goldenberg Saul , Ortiz Jayme Pinto , DeOliveira Gomes Paulo , Ramacciotti Eduardo
Published: March 2003

Abstract: The aim of this study was to evaluate the blood flow of an arteriovenous fistula comparing the modified latero‐lateral (LLM) and end‐lateral (TL) techniques in canine femoral arteries. Ten mongrel dogs were submitted to 2 arteriovenous fistulae each, with a LLM on one side and a TL procedure on the other side. Cranial and caudal average blood flow as well as average venous flow were measured by an electronic fluxometer 15, 20, and 25 min after surgery. Mann‐Whitney, Friedman, and Wilcoxon nonparametric tests were used for data analysis (α≤ 0,05). Femoral artery flow, cranial to the fistula, was increased 5½ times in both groups. In the femoral artery caudal to the fistula, the flow in the majority of the animals was reversed 1.3 times using the TL technique and 2 times using the LLM technique. The average flow in the cranial vein was statistically different with an improved flow of 7.4 times versus 6.8 times for the LLM technique. These results suggest that LLM arteriovenous fistula in dogs leads to a larger venous flow than in the TL arteriovenous fistula and the reverse caudal arterial flow in the latero‐lateral technique. The flow behavior (laminar or turbulent) in the 2 types of arteriovenous fistula was studied in terms of singular head loss.
Ultrasonic Pulsed Doppler Blood Flowmeter for Use in Extracorporeal Circulation
Authors: Dantas Ricardo Grossi , Costa Eduardo Tavares
Published: March 2003

Abstract: In cardiac surgeries, it is frequently necessary to make the external blood circulation and oxygenation artificially. This procedure is called extracorporeal circulation (EC) or heart‐lung bypass. During EC, one of the most important parameters, which demands continuous monitoring, is the blood flow. In many cases, the blood flow is estimated by the pump velocity (in roller pumps) or measured with transducers based on electromagnetic methods (in centrifugal pumps). This article presents an ultrasonic Doppler blood flowmeter to be used in the arterial line of an extracorporeal circulation system. The ultrasonic probe is coupled to a half‐inch tube connector of the extracorporeal arterial line, is not disposable, and does not need sterilization. The developed flowmeter revealed itself to be efficient and reliable and can be inserted in a closed‐loop pump controller system or be used as stand‐alone equipment.
A Small Pulsatile Blood Pump for Ventricular Support During End‐Stage Heart Failure
Authors: Förster Frank , Kaufmann Ralf , Reul Helmut , Rau Günter
Published: March 2003

Abstract: A displacement blood pump to support the natural heart of patients for recovery from end‐stage heart failure has been developed. This electromechanical pusher plate pump has a very compact and extremely flat design. The design goal was achieved by developing a novel gear system based on the principle of a swash plate. The blood pump and cannulae can be placed within the thoracic cavity between the lungs and ribcage. The first labtype model delivers an output of 3.1 L/min against an aortic pressure of 100 mm Hg at 120 bpm.
Development of a Miniature Undulation Pump for the Distributed Artificial Heart
Authors: Abe Yusuke , Ono Toshiya , Isoyama Takashi , Mochizuki Shuichi , Iwasaki Kiyotaka , Chinzei Tsuneo , Saito Itsuro , Kouno Akimasa , Imachi Kou
Published: March 2003

Abstract: Research of the distributed artificial heart is important not only to acquire the means of individual organ perfusion but also to clarify the characteristics of the organ and the mechanism of blood distribution. To investigate the distributed artificial heart, the miniature undulation pump was developed. The outer diameter and the thickness of the developed pump were 38 mm and 11 mm, respectively. The priming volume of the pump was 3.2 ml. The total size including the motor unit was 38 mm in diameter and 32 mm in length. The total weight was 67.5 g. The total volume was 27.5 ml. The pump was driven with pulse width modulation by using a 1 chip motor controller. More than 5 L/min of continuous output could be obtained. The results showed that the developed miniature undulation pump system had enough performance for individual organ perfusion.
Current Concepts in Tissue Engineering Technique for Repair of Cartilage Defect
Authors: Ochi Mitsuo , Uchio Yuji , Tobita Masatoshi , Kuriwaka Masakazu
Published: March 2003

Abstract: Hunter's observation in 1743 that cartilage “once destroyed, is not repaired,” has not essentially changed for 250 years. At present, there is no well‐established procedure for the repair of cartilage defect with articular cartilage, which has the same biochemical and biomechanical properties as the surrounding normal intact cartilage. In 1994, transplantation of human autologous chondrocytes in suspension, as reported by Brittberg et al., provided a potential procedure for articular cartilage repair. We have improved their procedure and developed a new technique which creates new cartilage‐like tissue by cultivating autologous chondrocytes embedded in Atelocollagen gel for 3 weeks before transplantation. These improvements maintained the chondrocyte phenotype, evenly distributed chondrocytes throughout the osteochondral defects, and decreased the risk of leakage of grafted chondrocytes into the defects. Good clinical results suggest that this technique should be a promising procedure for repairing articular cartilage defect.
A Honeycomb Collagen Carrier for Cell Culture as a Tissue Engineering Scaffold
Authors: Itoh Hiroshi , Aso Yu , Furuse Masayasu , Noishiki Yasuharu , Miyata Teruo
Published: March 2003

Abstract: As a three‐dimensional carrier for cell culture, a honeycomb structure cell scaffold was created from atelopeptide collagen Types I, II, and III. The diameter of the honeycomb pores ranged from 100 to 1,000 μm. The depth of the pores was from 10 to 3,000 mm. The scaffold was elastic and hard. Creation of various shapes was easy, and these shapes were easily maintained. Human fibroblasts, CHO‐K1, BHK‐21, and bovine endothelial cells were cultured with the scaffold. The growth curves of these cells were satisfactory. These results suggest that this carrier is a suitable scaffold for cell culture and will be useful as a three‐dimensional tissue engineering scaffold.
Extensive In Vivo Angiogenesis Following Controlled Release of Human Vascular Endothelial Cell Growth Factor: Implications for Tissue Engineering and Wound Healing
Authors: Elçin Y. Murat , Dixit Vivek , Gitnick Gary
Published: March 2003

Abstract: Vascular endothelial cell growth factor (VEGF) has strong stimulating effects on vascularization. Though very potent, VEGF is rapidly degraded due to its short half‐life and when administrated by uncontrolled and nonspecific methods; however, its systemic administration in large doses can cause harmful side effects. Controlled release technology would allow delivering desired levels of bioactive VEGF within extended periods and permit examination of the in vivo effects of the compound in a broader way. The objective of this study was to determine the in vitro release behavior of VEGF from calcium alginate microspheres and the potency of this controlled release system in promoting localized neovascularization at the subcutaneous site of the rat model. In vitro release of human VEGF165 (2 and 4 μg/cm3 microsphere) was studied for 3 weeks under static conditions at 25°C, and daily hormone release was measured using a competitive enzyme immunoassay. Following an uncontrolled release within the first 4 days, a quite constant zero‐order VEGF release of 50 to 90 and 70 to 120 ng/day was achieved from 2 and 4 μg/cm3 polymer loaded microspheres respectively. In vivo angiogenesis was studied for a period of 8 weeks and evaluated using immunoperoidase staining and histopathological measurements. In vivo studies with rats (n = 24) showed a considerable level of capillary network formation at the epigastric groin fascia of VEGF microsphere‐implanted rats starting from the first week. The most extensive neovascularization was observed in the group with 3 week postimplanted 4 μg VEGF containing microspheres; this level of vascularization was quite similar after 8 weeks. While the control group showed no evidence of angiogenesis, the difference in VEGF‐induced neovascularization is statistically significant (p < 0.03). Immunostaining of the specimens showed a strong relationship between the release of human VEGF and neovascularization. The controlled VEGF release system described here promotes vigorous angiogenesis and has applicability for tissue engineering and wound healing studies.
Growth of Endothelial Cells on Different Concentrations of Gly‐Arg‐Gly‐Asp Photochemically Grafted in Polyethylene Glycol Modified Polyurethane
Authors: Lin Yeong‐Shang , Wang Shoei‐Shen , Chung Tze‐Wen , Wang Yu‐Hsung , Chiou Sau‐Hwa , Hsu Jen‐Ji , Chou Nai‐Kuan , Hsieh Kou‐Huang , Chu Shu‐Hsun
Published: March 2003

Abstract: To improve endothelial cell adhesion and growth on the surface of polyethylene glycol modified polyurethane (PU‐PEG), cell adhesive peptide Gly‐Arg‐Gly‐Asp (GRGD) was photochemically grafted to the surface. The surface grafted GRGD‐N‐Succinimidyl‐6‐[4′‐azido‐2′‐nitrophenylamino]hexanoate (SANPAH) on a PU‐PEG surface was performed by adsorption and subsequent ultraviolet irradiation. Fourier transform infrared spectra (FTIR) and electron spectroscopy for chemical analysis (ESCA) confirmed the GRGD grafted to form a PU‐PEG‐GRGD surface. The composition fraction of nitrogen calculated from ESCA analysis for the PU‐PEG‐GRGD surface was well correlated with the concentration of GRGD to be immobilized. Human umbilical vein endothelial cells (ECs) were well adhered and growing on the PU‐PEG‐GRGD surface. Moreover, the viability of ECs growing on PU‐PEG‐GRGD surfaces, analyzed by MTT test, was also well correlated with the GRGD concentrations immobilized on the surface. With photochemical techniques, we could manipulate different contents of GRGD to form multiple regions of PU‐PEG‐GRGD surface that could enhance the growth of ECs on the surface, and the enhancement efficiency was well correlated with GRGD contents.
Antibacterial Effect of Antibiotic Solution on Cellular Viability in Canine Veins
Authors: Park Jong‐Chul , Sung Hak‐Joon , Lee Dong Hee , Park Young Hwan , Cho Bum Koo , Suh Hwal
Published: March 2003

Abstract: Pretreatment of tissue by using antibiotics is a critical step to prevent microbial contamination before venous transplantation. In this study, the optimal time and temperature of antibiotic solution treatment for maintaining cellular viability with antibacterial effect were investigated. The antibiotic‐nutrient solutions were composed of cefoxitin, lincomycin, vancomycin, and polymyxin B in RPMI‐1640 medium. After various antibiotic solution treatment times (4, 8, and 12 h) and temperatures (4, 25, and 37°C), the viabilities of cells dissociated from veins (jugular vein, femoral vein, superior vena cava, and inferior vena cava) were determined. Double staining by Griffonia simplicifolia agglutins–fluorescein isothiocyanate (GS1‐FITC) and propidium iodide was used. To measure the antibacterial effect of the antibiotic solution, canine veins were artificially infected by 3 kinds of bacteria (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and were treated by antibiotic solutions as viability test conditions. After the treatment with the antibiotic solution, the tissue was minced, and the homogenized tissue fraction was cultured on standard method agar. The colony that seemed to be resistant to the antibiotic solution was counted. At 37 and 25°C, the viability of whole cells decreased significantly Asymptotic Significance 2‐tailed (Asymp.Sig 2‐tailed) < 0.05 after 4 h of antibiotic solution treatment, whereas at 4°C it began to reduce significantly after 8 h of treatment. By antibiotic solution treatment at all 3 temperatures for 4 h, no significant difference in viability of the endothelial cells and whole cells was observed. To maintain the donor vein's cellular viability until transplantation, antibiotic solution treatment for 4 h at 4°C is assumed to be appropriate.
Antiinflammatory Effect of Heparin‐Coated Circuits with Leukocyte‐Depleting Filters in Coronary Bypass Surgery
Authors: Hamada Yoshihiro , Kawachi Kanji , Nakata Tatsuhiro , Kohtani Takashi , Takano Shinji , Tsunooka Nobuo
Published: March 2003

Abstract: Cardiac surgery with cardiopulmonary bypass is associated with a systemic inflammatory response. We examined combined use of heparin coating of the cardiopulmonary bypass circuit and a leukocyte‐depleting arterial line filter to reduce this response. Thirty patients were allocated randomly to equal groups with a conventional circuit and arterial line filter (C group), a heparin‐coated circuit with a conventional filter (H group), or a heparin‐coated circuit with a leukocyte‐depleting arterial line filter (HF group). Cytokines and respiratory function were repeatedly measured perioperatively. Plasma interleukin (IL)‐6 concentrations in the HF group were lower than in the C group immediately following bypass and operation, at 4 h, and 12 h (p < 0.05). Plasma IL‐8 was lower in the HF group than in the C group at 4 h (p < 0.05). The respiratory index was lower immediately after bypass in the HF group than the C group (0.61 ± 0.2 versus 1.05 ± 0.4, p < 0.05). Heparin‐coated circuits with leukocyte‐depleting filters decrease inflammatory responses and improve pulmonary function during operation.
HeartMate Left Ventricular Assist Devices: A Multigeneration of Implanted Blood Pumps
Authors: Maher Timothy R. , Butler Kenneth C. , Poirier Victor L. , Gernes David B.
Published: March 2003

Abstract: The HeartMate family of implanted left ventricular assist devices (LVADs) developed by Thermo Cardiosystems, Inc. (TCI) span a time frame that goes back to the beginning of clinical use of mechanical circulatory support and will stretch well into the foreseeable future. Associated blood pump technology employed in the HeartMates range from an original pusher plate concept to the most advanced rotary pump devices. Starting initially with a pneumatic actuated pusher plate pump, clinical use of the HeartMate I began in 1986. In 1990, electric motor‐actuated versions of the HeartMate I began to be used clinically. Presently, the HeartMate I has been implanted in some 2,300 patients worldwide, and this LVAD is a standard by which all others are currently measured. Following the HeartMate I is TCI's next‐generation, the HeartMate II, a rotary‐pump‐based LVAD that uses an axial flow blood pump having blood immersed mechanical bearings. Clinical trials of the HeartMate II were initiated in 2000. The HeartMate III, representing TCI's next‐generation LVAD, is structured around a centrifugal blood pump that uses a magnetically levitated rotating assembly. Compared to the HeartMate II, the HeartMate III has the potential for higher overall efficiency. The pump's operating life is not dependent on bearing wear. Given the significantly advanced LVAD technology represented by HeartMates II and III, coupled with the experience of HeartMate I, TCI is well‐poised to keep its LVAD products as industry standards in the future.
The Estimation of Cardiac Function from the Rotary Blood Pump
Authors: Nakata Kin‐ichi , Shiono Motomi , Akiyama Kenji , Orime Yukihiko , Saito Akira , Tutomu Hattori , Negishi Nanao , Sezai Yukiyasu , Sankai Yoshiyuki
Published: March 2003

Abstract: The rotary blood pump is implanted as a bridge to cardiac transplantation. Mechanical, histological, and biochemical improvements have been described in patients after implantation of left ventricular assist devices (LVADs). Thus, the rotary blood pump might be used as a bridge to recovery of myocardial function. However, unlike a pulsatile pump, the rotary blood pump cannot be stopped to estimate cardiac function: if the rotary blood pump stops, backflow will occur. In this study, a new method that can estimate cardiac function without pump stop was examined. Six pigs were the subjects of this acute study. The pump was implanted as an LVAD: the inlet cannula was inserted into the left ventricle, and the outlet cannula was inserted into the ascending aorta. The motor speed was regulated at a pump flow rate of 0 L/min at diastolic phase. Then, the relationship between the dp/dt of left ventricular pressure and external stroke work of actuator was examined. This method was studied at normal, hyperdynamic, and heart‐failure conditions. There was a high positive correlation between the dp/dt of left ventricular pressure and external stroke work of actuator. This method is useful and simple to estimate cardiac function without pump stop.
A Computational Study of the Effects of Inlet Guide Vanes on the Performance of a Centrifugal Blood Pump
Authors: Chan W.K. , Wong Y.W. , Yu S.C.M. , Chua L.P.
Published: March 2003

Abstract: This article presents computational studies on the effects of inlet guide vanes (IGVs) on the flow pattern and shear stress in a centrifugal blood pump. The effect of IGVs is to introduce a pre‐swirl to fluid particles entering the impeller with the intention that the fluid particles will travel along the blade profile. Currently, most commercial centrifugal blood pumps employ straight radial impeller blades that are not hydrodynamically ideal for a good flow pattern within the blade passage. Flow separation and formation of vortices within the blade passage are believed to increase the degree of hemolysis and thrombosis. These are causes for blood clotting that will lead to malfunctioning of ventricular assist devices. Four IGVs of different geometrical profiles have been numerically investigated using a commercial software program CFX‐Tascflow. The pump is operated at 2,000 rpm, and the results revealed that the relative flow patterns in the blade passage have been dramatically altered. The size of the vortices was reduced, and the pressure contours indicated a gradual rise from the impeller leading edge to the trailing edge. However, inclusion of IGV causes a drop in the pressure head generated. Higher frictional losses are incurred as fluid particles passed through the IGV. In addition, the IGV modifies the inlet velocity triangles, and this also contributes to a drop in the pressure head generated that is consistent with Euler's pump theory. The change in the flow patterns and the gradual variation of the pressure contours have led to lower shear stress within the blade passages as compared to the case without IGVs.
Modular Extracorporeal Liver Support
Authors: Sauer Igor M. , Gerlach Joerg C.
Published: March 2003

Abstract: Modular extracorporeal liver support (MELS) is an integrative concept for the treatment of hepatic failure with appropriate extracorporeal therapy units tailored to suit the actual clinical needs of each patient. The CellModule is a specific bioreactor charged with primary human liver cells harvested from human donor livers found to be unsuitable for transplantation due to steatosis, cirrhosis, or traumatic injury. The DetoxModule enables albumin dialysis for the removal of albumin‐bound toxins, reducing the biochemical burden of the liver cells and replacing the bile excretion of hepatocytes in the bioreactor. A DialysisModule for continuous venovenous hemofiltration can be added to the system if required in hepatorenal syndrome.
Numerical Investigation of the Effect of Blade Geometry on Blood Trauma in a Centrifugal Blood Pump
Authors: Chan W.K. , Wong Y.W. , Ding Y. , Chua L.P. , Yu S.C.M.
Published: March 2003

Abstract: Fluid dynamic forces in centrifugal blood pump impellers are of key importance in destruction of red blood cells (RBCs) because high rotational speed leads to strong interaction between the impeller and the RBCs. In this paper, three‐dimensional models of five different blade geometries are investigated numerically using the commercial software CFX‐TASCflow, and the streaklines of RBCs are obtained using the Lagrangian particle tracking method. In reality, RBCs pass through the pump along complicated paths resulting in a highly irregular loading condition for each RBC. In order to enable the prediction of blood damage under the action of these complex‐loading conditions, a cumulative damage model for RBCs was adopted in this paper. The numerically simulated percent hemoglobin (%HB) released as RBCs traversed the impeller and volute was examined. It was observed that the residence time of particles in the blade passage is a critical factor in determining hemolytic effects. This, in turn, is a function of the blade geometry. In addition, it was observed that the volute profile is an important influence on the computed HB% released.
Anemia and End‐Stage Renal Disease in the Developing World
Authors: Maïz Hédi Ben , Abderrahim Ezzeddine , Zouaghi Karim
Published: March 2003

Abstract: In developing countries, multiple comorbidities such as malnutrition, parasitoses, and hemoglobinopathies contribute to the aggravation of anemia observed in patients with end‐stage renal diseases. We analyze here the results of a retrospective evaluation of red‐cells indices and iron parameters conducted at the end of December 2000 in 304 prevalent Tunisian patients (sex ratio, 1.05; mean age, 53.7 years) receiving chronic hemodialysis for a median duration of 49.6 months (range, 1.6 to 278). Anemia, observed in 87.8% of patients, was normochromic and normocytic in 73% of cases. Only 2% of patients had microcytic and hypochromic anemia. Iron deficiency was observed in 21.6% of anemic patients. The mean rate of hemoglobin was significantly higher in men and in patients with polycystic kidney disease as the cause of renal failure. There was a positive correlation between hemoglobin values and the quality of dialysis. Only 10.8% of patients were on recombinant human erythropoietin (rHuEPO) and 38% required regular transfusions. We conclude that anemia observed in our patients had, in most cases, the characteristics of renal anemia and could be attributed to a deficit of renal production of erythropoietin. However, for financial reasons, prescription of rHuEPO is rather restrictive and blood transfusion remains largely used. The nephrology community and dialysis providers should increase their efforts to improve the anemia care of dialyzed patients in developing countries.
Contributions of a Finite Element Model for the Geometric Optimization of an Implantable Bioartificial Pancreas
Authors: Dulong Jean‐Luc , Legallais Cécile
Published: March 2003

Abstract: The extravascular implantation of islets of Langerhans immunoprotected within a permselective membrane is a promising method to treat diabetes mellitus. However, oxygen limitation due to purely diffusive solute transport was considered to provoke tissue necrosis and graft failure. We built a solute transport model based on a finite element method aiming at optimizing the hollow fiber geometry. With a low islet density, the influence of oxygen axial flux inside the fiber was underlined and a characteristic length for oxygen supply was introduced. This study allowed the conclusion that islet density must be adapted to the fiber diameter chosen for implantation.
Morphological Changes of the Arterial Systems in the Kidney under Prolonged Continuous Flow Left Heart Bypass
Authors: Ohnishi Hiroyuki , Itoh Tsuyoshi , Nishinaka Tomohiro , Tatsumi Eisuke , Fukuda Toshihide , Oshikawa Mitsuo , Shioya Kyoko , Tsukiya Tomonori , Takewa Yoshiaki , Homma Akihiko , Uesho Kunihiro , Sato Koichi , Takano Hisateru , Taenaka Yoshiyuki
Published: March 2003

Abstract: We investigated morphological changes of the arterial systems in the kidneys under prolonged continuous flow left heart bypass. Twelve goats were subjected to 2 weeks of pulsatile left heart bypass followed by 4 weeks of continuous flow left heart bypass (group CF). After autopsy, the kidneys underwent pathological evaluation. Six normal healthy goats were used as controls. The media of the afferent arterioles of group CF were frequently thickened by an increase in the number of the mature smooth muscle cells (SMCs). The juxtaglomerular areas (JGA) were expanded because of an increase in the number and size of SMCs and/or SMC‐like cells. Furthermore, the percentage of anti‐proliferating cell nuclear antigen antibody–positive cells in the JGA of group CF (9.9 ± 1.9%) was significantly higher (p = 0.025) than that of the control group (4.6 ± 3.4%), indicating active proliferation in group CF. We concluded that prolonged continuous flow left heart bypass causes proliferation of SMCs and/or SMC‐like cells in the afferent arterioles and their perivascular tissue.
Impeller Inner Diameter in a Miniaturized Centrifugal Blood Pump
Authors: Takano Tamaki , Schulte‐Eistrup Sebastian , Kawahito Shinji , Maeda Tomohiro , Nonaka Kenji , Linneweber Joerg , Glueck Julie , Fujisawa Akira , Makinouchi Kenzo , Yokokawa Michihiro , Nosé Yukihiko
Published: March 2003

Abstract: To design a miniaturized centrifugal blood pump, the impeller internal diameter (ID), which is a circle diameter on the inner edge of the vane, is considered one of the important aspects. Hydraulic performance, hemolysis, and thrombogenicity were evaluated with different impeller IDs. Two impellers were fabricated with an outer diameter of 35 mm, of which 1 had an 8 mm ID impeller and the other had a 12 mm ID. These impellers were combined with 2 different housings in which the inlet port was eccentrically positioned 3.8 and 4.5 mm offset from the center. The hydraulic performance and hemolysis were evaluated in a mock circuit, and thrombogenicity was evaluated in a 2 day ex vivo study with each impeller housing combination. Both impellers required 3,000 rpm in the 3.8 mm offset inlet to attain 5 L/min against 100 mm Hg (left ventricular assist device condition). The 8 mm ID impeller required 3,200 rpm, and the 12 mm ID impeller required 3,100 rpm in the 4.5 mm offset housing. The normalized index of hemolysis was 0.0080 ± 0.0048 g/100 L in the 8 mm ID impeller with the 3.8 mm offset and 0.022 ± 0.018 g/100 L with 4.5 mm offset. The 12 mm ID impeller had 0.068 ± 0.028 g/100 L with the 3.8 mm offset and 0.010 ± 0.002 g/100 L with the 4.5 mm offset. After the 2 day ex vivo study, no blood clot was formed around the top bearing in all the pump heads. The 8 mm ID impeller with 3.8 mm offset inlet and the 12 mm ID impeller with the 4.5 mm offset had less hemolysis compared to the other pump heads that were subjected to 14 day ex vivo and 10 day in vivo studies. The 8 mm ID impeller with the 3.8 mm offset inlet had a blood clot around the top bearing after the 14 day ex vivo study. No thrombus was found around the top bearing of the 12 mm ID impeller with the 4.5 mm offset in the 10 day in vivo study. These results suggest that the ID does not greatly change the hydraulic performance of a small centrifugal blood pump. The proper combination of the impeller ID and inlet port offset obtains less hemolysis. The larger impeller ID is considered to have less thrombogenicity around the top bearing.
Evaluation of Hemolysis in the VentrAssist Implantable Rotary Blood Pump
Authors: James Natalie L. , Wilkinson Carmel M. , Lingard Nicole L. , Meer Anita L. van der , Woodard John C.
Published: March 2003

Abstract: The VentrAssist implantable rotary blood pump (IRBP) is an implantable centrifugal blood pump with a hydrodynamically suspended impeller; optimal efficiency requires small running clearances (70–300 μm). The effect of running clearance and polish on hemolysis was evaluated in vitro. Three different human blood suspensions were compared: phosphate buffered saline (PBS), plasma volume expander (Hemaccel), and whole blood. The test conditions were: blood hematocrit 30%, flow rate 5 L/min, pressure across pump 100 mm Hg, 6 h flow period, and 37°C. Normalized Index of Hemolysis (NIH) for the Biomedicus BP‐80, used as a control, was: 0.0040 ± 0.0023 (n = 9; x ± SD) and 0.00014 ± 0.00009 (n = 5) for pooled blood suspensions in PBS and Hemaccel respectively, and 0.00053 ± 0.0002 (n = 3) in whole blood. Hemolysis was reduced by improved surface finish and unaffected by running clearance. NIH for the VentrAssist IRBP with 0.2 μm Ra surface finish was 0.000167 ± 0.00007 (n = 4) g/100 L in whole human blood, demonstrating minimal hemolysis.
Elevated Blood Lead Concentrations in Children Living in Isolated Communities of the Kola Peninsula, Russia
Authors: Odland Jon Øyvind , Perminova Irina , Romanova Natalya , Thomassen Yngvar , Tsuji Leonard J.S. , Brox Jan , Nieboer Evert
Published: March 2003

ABSTRACT Lead levels were determined in children aged 5–14 in three communities: two groups (N = 24 and 39) from Apatity, an industrial city; a group (N = 47) from Lowozero, an isolated Saami village; and another (N = 14) from Krashnochelie, a remote native village with Sami, Komi, and Nenets populations. As in the northwestern James Bay region of Canada, unexpectedly high blood lead concentrations were found in the most isolated community, namely Krashnochelie. The median lead concentration in Krashnochelie was significantly higher (p < 0.01 or p < 0.02) than those for the other village and city. In the Krashnochelie group, the lead levels were not gender dependent. The percentage of children with blood lead concentrations at or above the medical concern level of 0.48 μmol/l was highest (36%) in Krashnochelie, compared to 8% in Apatity and 6% in Lowozero. All but two of the 124 individuals tested had ferritin concentrations above that indicative of depleted iron stores (10 μg/l for age <14 years); the median ferritin values were comparable for all four communities. Iron status differences can therefore not explain the elevation of blood lead concentrations in the Krashnochelie group. A number of explanations are provided to account for the implied differences in lead exposure in the four study groups.
Auditing the Health of Australia's Ecosystems
Authors: Tait Jim T.P. , Cresswell Ian D. , Lawson Rochelle , Creighton Colin
Published: March 2003

ABSTRACT The Australian Government has made a commitment to a National Land and Water Resources Audit (Audit) to provide data, analysis, and appraisal of natural resource management and to facilitate improved decision making at a range of scales. One of the themes within the Audit is ecosystem health. This article describes the goals of the Audit with respect to ecosystem health and provides examples of how these goals are being realized in terms of projects. Six projects within the ecosystem health theme of the Audit are described. Benefits of the ecosystem health paradigm have been recognized by the Audit in comparison to previous natural resource assessment methods that tended to focus on single components of ecosystems through the use of environmental quality indicators and often failed to make distinctions and linkages between ecosystem types. A “catchment to estuary” concept which identifies the linkages between landscape, catchment, waterway, and estuarine condition is providing the rationale behind the process‐based integration of natural resource data sets which form the basis of methods being developed by the Audit. This depends upon the identification of key ecosystem process drivers and a range of attributes by which they may be measured at appropriate scales. The Audit's aim is to develop purpose‐driven multiattribute assessment frameworks that can incorporate a range of available natural resource information along with social and economic data to provide a measure of distance of ecosystems from some desired state. The contributions of other Audit theme projects to such assessments and the final integrated reporting requirements of the Audit across disciplinary themes is described. Perceived benefits of the ecosystem health approach to natural resource assessment and tests of effectiveness that may be used by the Audit are also discussed.
Agriculture for Health and Profit in Western Australia: The Western Oil Mallee Project
Authors: Bell Sarah J. , Barton Allan F.M. , Stocker Laura J.
Published: March 2003

ABSTRACT Land cleared for agriculture in Western Australia has become severely degraded as deep‐rooted native perennial vegetation has been replaced with annual cereal crops. Dryland salinity is the most severe form of land degradation in this region. The Western Oil Mallee Project has the potential to provide an ecologically sustainable solution to problems associated with land clearing, including dryland salinity. The project involves local farmers planting native eucalypt species which may be harvested to produce eucalyptus oil, electricity and activated carbon. Some potential benefits of an ecologically sustainable approach to industry development include reduced land degradation, increased biodiversity, increased local employment, diversified farm production and higher local community capacity.
Applied Ethics in Human and Ecosystem Health: The Potential of Ethics and an Ethic of Potentiality
Authors: Albrecht Glenn A.
Published: March 2003

ABSTRACT We live at a time when billions of people on this earth cannot achieve their full potential. Their lives are cut short or impoverished by malnutrition, pollution, and disease caused by failure of ecosystem and social services. In addition, if we were to project the quality of life enjoyed by those in advanced industrial countries to the world's poor, we would need about two planets to satisfy the demands for resources and waste assimilation services. Superimposed on the degradation of social systems, ecosystems worldwide are experiencing major threats to their integrity and health. Excessive human impacts are degrading ecosystem service provision, breaking and contracting food chains and making them less productive. Despite a growing understanding of social and ecosystem dysfunctionality, there remains little movement toward social sustainability and the restoration of the health of ecosystems worldwide. This paper presents an ethical foundation for those who seek sustainability. The key to such an applied ethic is the idea of directionality, where the natural tendency toward increasing complexity and diversity in complex adaptive systems provides guidance on what constitutes a sustainable society. The achievement of such a society can be facilitated by an ethic of potentiality that will assist humans to reintegrate ecosystem and human health.
The Site of Sympathetic Deficit in Cluster Headache
Authors: Drummond Peter D.
Published: March 2003

The pattern of autonomic deficit in the face of cluster headache patients resembles the deficit in patients with a postganglionic sympathetic lesion from some other cause; however the presence of abnormal cardiac rhythms and bilateral pupillary reflex deficit in some patients with cluster headache suggests that the lesion might compromise central sympathetic drive. To investigate this possibility, the vasomotor and sudomotor startle reflex was investigated in the hands of sic cluster headache patients with ocular and thermoregulator signs of postganglionic sympathetic deficit in the face; for comparison, responses were also investigated in 15 patients with a lesion in the cervical sympathetic pathway from some other cause. The startle reflex was intact in the hands of the six cluster headache patients, but was diminished ipsilaterally in patients with a central or preganglionic sympathetic lesion and also, surprisingly, in patients with a postganglionic lesion caused by an aneurysm of the internal carotid artery. Ocular sympathetic deficit was greater in patients with an aneurysm of the internal carotid artery than in cluster headache patients or in patients with a postganglionic sympathetic lesion from some other cause; the aneurysm may have compromised neurons with projections to the face and hand, or could have induced transsynaptic degeneration of preganglionic fibers supplying both regions. The findings indicate that central sympathetic drive is not impaired in cluster headache patients; thus, a peripheral lesion probably induces sympathetic deficit on the symptomatic side of the face.
Occipital Nerve Release in Patients With Whiplash Trauma and Occipital Neuralgia
Authors: Magnússon Torfi , Ragnarsson Thórir , Björnsson Al on
Published: March 2003

The results of 18 greater occipital nerve release operations in 13 patients were analyzed. All patients had deep aching pain in the occipital area due to a whiplash trauma, and in all cases the pain was relieved temporarily by local anesthesia of the occipital nerve. The time from accident to operation was 6 to 96 months. The results of 13 (72.2%) operations were reported as good or excellent, although complete pain relief was not attained in any patient. It is concluded that neurolysis of the greater occipital nerve after whiplash injury can give meaningful pain relief in selected patients.
Migraine and Angina Pectoris by Coronary Artery Spasm
Authors: Lafitte Catherine , Even Christian , Henry‐Lebras Francoise , de Toffol Bertrand , Autret Alain
Published: March 2003

A migrainous patient who experienced chest pain attributed to engine pectoris by coronary artery spasm during a migraine attack is reported. Previous reports have already mentioned the association of these two conditions and suggested that it might be the manifestation of a generalized vasospastic disorder. This new report offers an opportunity to review and discuss the available data on such an association.
Cardiac Arrest Caused by Trigeminal Neuralgia
Authors: Gottesman Malcolm H. , Ibrahim Bassiema , Elfenbein Alexander S. , Mechanic Allan , Hertz Sharon
Published: March 2003

A 67‐year‐old man with a 12‐year history of trigeminal neuralgia experienced multiple fainting episodes preceded by right facial pain. One episode resulted in cardiac arrest with successful resuscitation. Pacemaker insertion prevented further episodes of syncope despite the occurrence of pain. The fainting episodes and cardiac arrest are believed to be unusual manifestations of trigeminal neuralgia.
A New Instrument to Assess the Long‐term Quality of Life Effects From Migraine: Development and Psychometric Testing of the MSQOL
Authors: Wagner T.H. , Patrick D.L. , Galer B.S. , Berzon R.A.
Published: March 2003

Quality of life is important to persons experiencing migrains. This study discusses the development of a migraine‐specific quality‐of‐life measure (MSQOL). Participants, who included migraineurs from both tertiary care centers and the community, were screened using the International Headache Society migraine criteria prior to enrollment. Internal consistency of the MSQOL was high (alpha 0.92). Reproducibility over an average of 24 days was high (intraclass correlation 0.90). Construct validity was determined by convergent validity and known groups validity. The MSQOL was compared to two other frequently used health status questionnaires; results indicate that the MSQOL more closely resembles well‐being then functional status. Results also indicate that migraineurs with more symptoms, medical appointments per year to treat migraines, and migraine episode per year have a significantly worse quality of life. The MSQOL proved valid and reliable as a serf‐administered measure and will be a useful tool in clinical migraine research. The information gained from its use in the clinical environment should provide important additional information about the impact of migraine on quality of life and the potential benefits of therapeutic interventions.
Headache in a Population‐Based Elderly Cohort. An Ancillary Study to the Italian Longitudinal Study of Aging (ILSA)
Authors: Franceschi Massimo , Colombo Bruno , Rossi Paolo , Canal Nicola
Published: March 2003

The aims of this ancillary study to the Italian Longitudinal Study of Aging were: (1) to provide reliable prevalence data on headache in an elderly population, (2) to classify the subtypes of headache according to International Headache Society criteria, and (3) to identify possible risk factors and associated pathologies in the elderly.

A total of 312 subjects were examined, 148 women and 164 men, with a mean age of 73 years (SD 5.5). For 236 subjects (75.7%), 141 men (85.9%) and 95 women (64.2%), headache had never been a problem; 57 subjects (18.3%), 21 men (12.8%) and 36 women (24.3%), reported troublesome headache only in the past. Nineteen subjects (6%), 6 men (3.6%) and 13 women (8.8%), reported current headache: in this group tension‐type headache was the most prevalent, accounting for 2.6%; secondary headaches ranked second, accounting for 2.2%; and only 1% had current migraine.

Our data indicate female sex and younger age as risk factors for headache, and associate migraine and secondary headaches with hypertension, tension‐type headaches and secondary headaches with diabetes, and tension‐type headaches with myocardial ischemia.