bluuebunny/crossref_metadata_2025 huggingface dataset:
Centrifugal Pumps and Heparin‐Coated Circuits in Surgical Treatment of Giant Cerebral Aneurysms
Authors: Mesana Thierry , Collart Frédéric , Caus Thierry , Pomane Claude , Graziani Noel , Bruder Nicolas , Dufour Henry , Grisoli François , Montiès Jean Raoul
Published: March 2003

Abstract: Giant cerebral aneurysms may be untreatable by conventional neurosurgical techniques. Early attempts to use circulatory assistance and deep hypothermia were abandoned due to hemorrhagic complications. More recently, interest in circulatory support for complex neurosurgical procedures has been renewed. A consecutive series of 8 patients were operated on for giant cerebral aneurysms with the combined use of deep hypothermia. The protocol included careful preoperative cardiovascular assessment, perfect intraoperative synergy between neurosurgical and cardiac teams, minimally invasive peripheral vascular access including two femoral vein (21 F) and single arterial (17 F) femoral cannulation, use of total Carmeda coating on BioMedicus pumps in closed circuits, and reduced heparinization without Protamine reversal. All cerebral aneurysms were successfully treated through deep hypothermia (15–18°C) as assessed by intraoperative fluoroscopic controls and Doppler vascular assessment. Mean circulatory support time was 174.2 ± 29.6 min. Circulatory arrest period was 20 ± 12 min. All patients survived and were extubated within 48 h. No major deficit was observed clinically or on postoperative CT scan. No hemorrhagic complications occurred (mean transfusions was 2.2 blood units). This work supports an extensive use of heparin‐coated surfaces for complex circulatory assist techniques, either for cardiac or extra cardiac complex procedures.
Computational Fluid Dynamics Analysis of a Centrifugal Blood Pump with Washout Holes
Authors: Tsukamoto Yuki , Ito Kazuyuki , Sawairi Toshio , Konishi Yoshiaki , Yamane Takashi , Nishida Masahiro , Masuzawa Toru , Tsukiya Tomonori , Endo Seiko , Taenaka Yoshiyuki
Published: March 2003

Abstract: The authors studied avoidance of coagulation occurrence using computational fluid dynamics (CFD) analysis from the fluid dynamical point of view. Concerning centrifugal pumps, blood coagulation sometimes occurs at the region behind the impeller where the flow is generally stagnant. Therefore, we conducted a thorough study with the specimen pump with and without washout holes, mocking up the Nikkiso HPM‐15. As the result, the model with washout holes indicated that the fluid rotates rapidly at the vicinity of the shaft and generates washout effects near the stationary rear casing. On the other hand, the model without washout holes showed that fluid cannot be quickly shipped out of the area behind the impeller and rotates mildly around the shaft. To clarify the moving relations between the impeller and the fluid, validation studies by comparing the results of CFD analysis and flow visualization experiments are ongoing; thus far, the studies show that CFD results are similar to the results from flow visualization experiments.
In Vivo Kinematic Analysis of Total Knee Arthroplasty with Four Different Polyethylene Designs
Authors: Wada Makoto , Tatsuo Hiroshi , Kawahara Hideo , Sato Mitsuhiko , Baba Hisatoshi
Published: March 2003

Abstract: The femorotibial contact point on the sagittal plane was measured under weight‐bearing conditions in 45 subjects with implanted and nonimplanted knees. They consisted of 11 knees with flat bearing inserts, 16 knees with shallow dished inserts, 10 knees with posterior lipped inserts, 10 knees with posterior stabilized bearing inserts, and 8 normal knees selected as controls. The average amount of anterior translation of the knee with a flat bearing insert was significantly larger than that of the other implanted knees. The average femorotibial contact point did not differ significantly among knees with shallow dished, posterior lipped, and posterior stabilized bearing inserts, but posterior stabilized knees exhibited most frequently a normal posterior movement. Based on our results, it may be safer to use more anteroposterior constrained bearing inserts in total knee arthroplasty, particularly when the posterior cruciate ligament is loose.
A Pulsatile Pneumatically Driven Neonatal Extracorporeal Membrane Oxygenation System Using Neck Vessel Cannulas Tested with Neonatal Mock Circulation
Authors: Trittenwein Gerhard , Burda Gudrun , Trittenwein Hildegard , Golej Johann , Hermon Michael , Pollak Arnold
Published: March 2003

Abstract: In posthypoxic circulatory failure, pulsatility of flow generated by mechanical support devices significantly influences outcome. Pneumatically driven assist devices can create highly pulsatile flow, but need large graft cannulas implanted by thoracotomy in children and neonates. Emergency application is therefore hindered. We conducted an in vitro study using neonatal mock circulation (NMC) to test whether an extracorporeal membrane oxygenation (ECMO) system driven by a commercially available pneumatic assist device also can be operated through commonly used neonatal neck vessel cannulas. Using the pneumatically operated Medos ventricular assist device (VAD) 10 ml ventricle along with the Jostra M8/HEC40 oxygenator/heat exchanger, a neonatal ECMO system was assembled and connected to the NMC by means of commercially available neonatal neck vessel cannulas. Effective ECMO flow, combined circulation flow, and circulation pressures were measured during various working settings (ventricle driving pressures [systolic/diastolic (mbar)]: low: +100/−25, moderate: +200/−50, high: +300/−99) and loading conditions (device working against 0, 50, and 100% native circulation flow). Additionally, maximum possible ECMO flow through various sizes of neonatal ECMO cannulas and resulting pressure gradients were assessed. High pressure settings were necessary to achieve 100 ml/kg/min pulsatile circulation flow in case of zero native circulation. With residual 30% native circulation flow, 100 ml/kg/min pulsatile circulation flow could be established by moderate pressure settings. Low preload or high systemic vascular resistance reduced ECMO flow markedly. We concluded that in the described setting a pneumatically driven neonatal ECMO system could be operated even through commonly used neonatal neck vessel cannulas. It was necessary to accept partial emptying of the artificial ventricle and tapering of driving pressures with increasing native circulation.
Oxygen Transfer in a Convection‐Enhanced Hollow Fiber Bioartificial Liver
Authors: Hay P.D. , Veitch A.R. , Gaylor J.D.S.
Published: March 2003

Abstract: A mathematical model was developed to predict oxygen transport in a hollow fiber bioartificial liver device. The model parameters were taken from the HepatAssist 2000 device, a plasma perfused hollow fiber cartridge with primary hepatocytes seeded in the extracapillary space. Cellular oxygen uptake was based on Michaelis‐Menten kinetics. Oxygen transport due to the convective flow of plasma into the extracapillary space was considered. The effect of modulating several important parameters was investigated, namely, the Michaelis‐Menten constant Vm (the maximum oxygen consumption per unit volume of the cell mass), the oxygen partial pressure, the flow rate of the plasma at device inlet, and the permeability of the cell mass contained in the extracapillary space. A computer implementation of the model was used to assess whether a given number of cells could be maintained within such a device. The results suggest that a substantial proportion of the hepatocytes are exposed to hypoxic conditions under which metabolism may be impaired.
Clinical Long‐Term Results of Vascular Prosthesis Sealed with Fragmented Autologous Adipose Tissue
Authors: Karube Norihisa , Soma Tamitaro , Noishiki Yasuharu , Yamazaki Ichiya , Kosuge Takayuki , Ichikawa Yukio , Takanashi Yoshinori
Published: March 2003

Abstract: Tissue engineering can improve the former limitations of artificial organs. This article reports the long‐term clinical results of grafts constructed with fragmented autologous adipose tissue. We did a retrospective analysis of a series of 53 patients with lower leg ischemia that received 69 fragmented adipose tissue (FAT) grafts implantation at our institution. The mean follow‐up period was 36.0 months. After 1, 2, 3, and 5 years, the primary potency rates were 85.3, 83.3, 73.8, and 67.7%, respectively. The lumen of occluded areas not only at anastomotic sites but also in areas far from the anastomotic sites was occupied by a thickened neointima, which had a great number of capillary blood vessels, elastic laminae, smooth muscle cells, fibroblasts, and collagen fibers. This type of intimal hyperplasia was a characteristic finding in the FAT grafts. From the results of this clinical trial, we conclude that the FAT grafts are acceptable as vascular prostheses for ischemic lower extremities. The intimal hyperplasia at sites far from the anastomotic lines suggested the possibility of neointima formation throughout the luminal surface of the grafts.
Assessment of Hemolysis Related Quantities in a Microaxial Blood Pump by Computational Fluid Dynamics
Authors: Apel Jörn , Paul Reinhard , Klaus Sebastian , Siess Thorsten , Reul Helmut
Published: March 2003

Abstract: A computational assessment or even quantification of shear induced hemolysis in the predesign phase of artificial organs (e.g., cardiac assist devices) would largely decrease efforts and costs of design and development. In this article, a general approach of hemolysis analysis by means of computational fluid dynamics (CFD) is discussed. A validated computational model of a microaxial blood pump is used for detailed analysis of shear stress distribution. Several methods are presented that allow for a qualitative assessment of shear stress distribution and related exposure times using a Lagrangian approach and mass distribution in combination with shear stress analysis. The results show that CFD offers a convenient tool for the general assessment of shear‐induced hemolysis. The determination of critical regions and an estimation of the amount of blood subject to potential damage in relation to the total mass flow are shown to be feasible. However, awareness of limitations and potential flaws in CFD based hemolysis assessments is crucial.
Recent Progress on Transcutaneous Energy Transfer for Total Artificial Heart Systems
Authors: Puers R. , Vandevoorde G.
Published: March 2003

Abstract: For many years, transcutaneous energy transfer (TET) systems have been developed for energizing total artificial heart systems. Although such a basic system can be developed without too much design effort, optimization toward high power transfer efficiency forces the introduction of novel system topologies and design strategies. In addition, for medical applications, the thermal impact of a TET system on the biological tissue should be taken into account, resulting in limitations on usable coil geometries. This article presents a TET system that has been developed for a power transfer of 25 W over a distance of 1 cm with minimal dimensions of 1 × 6 × 4 cm for the external driver and 5 × 3 × 1 cm for the internal electronics. The coil geometries have a thickness of 2 mm and a diameter of 6 cm. An overall system efficiency of 80% was achieved for an internal load of 25 W.
Osteogenic Evaluation of Glutaraldehyde Crosslinked Gelatin Composite with Fetal Rat Calvarial Culture Model
Authors: Liu Hwa‐Chang , Yao Chun‐Hsu , Sun Jui‐Sheng , Lee Chun‐Jean , Huang Chin‐Wang , Lin Feng‐Huei
Published: March 2003

Abstract: The cytotoxicity of the synthetic bone substitute composed of tricalcium phosphate and glutaraldehyde crosslinked gelatin (GTG) were evaluated by osteoblast cell culture. In a previous study, the GTG composites were soaked in distilled water for 1, 2, 4, 7, 14, 28, and 42 days, and then the solutions (or extracts) were cocultured with osteoblasts to evaluate the cytotoxicity of GTG composites by alive cell counting. In this study, the extracts were cocultured with the osteoblasts; thereafter, the concentration of transforming growth factor‐β (TGF‐β1) and prostaglandin E2 (PGE2) in the medium was analyzed to strictly reflect the biological effects of GTG composites on the growth of osteoblasts. In order to investigate the osteoconductive potential of the GTG composites on new bone formation in a relative short term, a model of neonatal rat calvarial organ culture was designed prior to animal experiments. Three experimental materials of 4, 8, and 12% GTG composites were evaluated by fetal rat calvarial organ culture for their ability for bone regeneration. Deproteinized bovine and porcine cancellous bone matrixes were used as the controlled materials. All the organ culture units were maintained in cultured medium for 5 weeks. Following the culture period, the morphology of tissue was observed under an optical microscope, and the quantitative evaluation of the new generation bone was determined by using a semiautomatic histomorphometeric method. Except in the initial 4 days, the concentration of TGF‐β1 of 4% and 8% GTG composites was higher than that of the blank group for all the other experimental time periods. The PGE2 concentration for 4% and 8% GTG composites was lower than that of the blank group. It revealed that the 4% and 8% GTG composites would not lead to inflammation and would promote osteoblast growth. The morphology and activity of the osteoblasts were not transformed or changed by the 2 GTG composites. For the 12% GTG composite, the performance of the in vitro condition was inferior to the blank group and the other 2 GTG composites. Although the concentration of TGF‐β1 and PGE2 was gradually back to normal after 14 days, the morphology of the osteoblasts was abnormal with features such as contracted cytoplast structures. The osteoblast was damaged perhaps in the initial stage. We suggested that the 4% and 8% GTG composites should be soaked in distilled water at least for 4 days before medical applications. The 12% GTG composite and the composites with a concentration of glutaraldehyde solution higher than 12% were not recommended as a medical prostheses in any condition. The fetal rat calvaria culture also showed the same results with the analysis of TGF‐β1 and PGE2. From the study, we could predict the results of animal experiments in the future.
Inlet Port Positioning for 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: We are developing the Baylor‐Kyocera KP implantable centrifugal blood pump for small sized adult and pediatric patients. This pump eccentrically positions the inlet port, which eliminates flow stagnation around the top pivot bearing. The inlet port design is important because it may vary the inlet orifice pressure on the top housing and change hydraulic performance and hemolytic characteristics. The pressure distribution inside the KP pump was assessed by a computational fluid dynamic (CFD) analysis with 2.7 × 105 elements and 3.16 × 105 nodes. Hydraulic performance and hemolysis were evaluated with 3 different pump housings, which had 3.8, 4.5, and 6.1 mm offset inlet ports from the center in a mock circuit. The CFD analysis revealed that the pressure gradually increased from the center toward the peripheral. The pressure difference between the 3.8 to 6.1 mm offsets was less than 600 Pa. The hydraulic performance did not drastically change at 3.8, 4.5, and 6.1 mm offset from the center. However, the hemolysis increased with the increase of the port offset from 0.0080 ± 0.0048 to 0.054 ± 0.028 g/100 L. The inlet port positioning is important to attain less blood trauma in this small Gyro centrifugal blood pump. The preferable position of the inlet port is less than 4.5 mm offset from the center.
Polyetherimide: A New Membrane‐Forming Polymer for Biomedical Applications
Authors: Seifert B. , Mihanetzis G. , Groth T. , Albrecht W. , Richau K. , Missirlis Y. , Paul D. , Von Sengbusch G.
Published: March 2003

Abstract: Membranes for biohybrid organs such as the biohybrid liver support system have to face 2 different environments, namely blood and tissue cells. Accordingly, the respective membrane surfaces must have optimal properties in terms of biocompatibility for blood or tissue. Flat membranes prepared by a phase inversion process from polyetherimide were modified by binding of tris‐(hydroxymethyl)‐aminomethane to obtain a surface with hydroxyl groups by binding of polyethylene imine to attach a hydrophilic macromolecule with amine groups useful as a spacer for later bonding of further ligands and by attachment of heparin. The binding of the different ligands was successful as monitored by different physicochemical methods. The blood response of plain polyetherimide was comparable to that of polyacrylonitrile, and it could be further improved by the binding of heparin. The tissue compatibility of polyetherimide and its different modifications was compared with commercial cell culture substrate membranes (Millicell) and found to be comparable for polyetherimide and even better after the modification with tris‐(hydroxymethyl)‐aminomethane. In conclusion, polyetherimide seems to be an interesting material for the production of membranes for application in biohybrid organ systems.
Denervated Muscles in Humans: Limitations and Problems of Currently Used Functional Electrical Stimulation Training Protocols
Authors: Kern Helmut , Hofer Christian , Mödlin Michaela , Forstner Claudia , Raschka‐Högler Doris , Mayr Winfried , Stöhr Hans
Published: March 2003

Abstract: Prior clinical work showed that electrical stimulation therapy with exponential current is able to slow down atrophy and maintain the muscle during nonpermanent flaccid paralysis. However, exponential currents are not sufficient for long‐term therapy of denervated degenerated muscles (DDMs). We initiated a European research project investigating the rehabilitation strategies in humans, but also studying the underlying basic scientific knowledge of muscle regeneration from satellite cells or myoblast activity in animal experiments. In our prior study, we were able to show that high‐intensity stimulation of DDMs is possible. At the beginning of training, only single muscle twitches can be elicited by biphasic pulses with durations of 120–150 ms. Later, tetanic contraction of the muscle with special stimulation parameters (pulse duration of 30–50 ms, stimulation frequency of 16–25 Hz, pulse amplitudes of up to 250 mA) can improve the structural and metabolic state of the DDMs. Because there are no nerve endings for conduction of stimuli, large‐size, anatomically shaped electrodes are used. This ensures an even contraction of the whole muscle. Contrary to the current clinical knowledge, we were able to stimulate and train denervated muscle 15–20 years after denervation. The estimated amount of muscle fibers that have to be restored is about 2–4 million fibers in each m. quadriceps. To rebuild such a large number of muscle fibers takes up to 3–4 years. Despite constant stimulation parameters and training protocols, there is a high variation in the developed contraction force and fatigue resistance of the muscle during the first years of functional electrical stimulation.
Ten Year Clinical Experience with the CarboMedics Heart Valve Implants
Authors: Kuwaki Kenji , Tsukamoto Masaru , Komatsu Kanshi , Sakata Junichi , Abe Tomio
Published: March 2003

Abstract: We reviewed the histories of 144 patients who underwent heart valve replacement with the CarboMedics prosthesis from 1990 to 2000. There were 74 males and 70 females, with a mean age of 52 years, including 69 aortic valve replacements, 48 mitral valve replacements, and 27 double (aortic and mitral) valve replacements. The mean duration of follow‐up was 6.5 years. Early mortality was 7.6% (11 patients). Late deaths occurred in 14 patients, including cardiac‐related late deaths in 9 and valve‐related deaths in 3. The survival rate including early deaths was 84.7 ± 3.2% at 5 years and 78 ± 4.1% at 10 years. Preoperative New York Heart Association Class IV (p = 0.0001) was found to be a significant predictor of cardiac‐related late death. Freedom rate from complications at 10 years were embolism 84.7 ± 4.2% (linearized rate 1.8% per patient year), valve thrombosis 92.7 ± 2.7% (linearized rate 0.8% per patient year), bleeding 95.6 ± 2.6% (linearized rate 0.4% per patient year), reoperation 85.9 ± 4% (linearized rate 1.5% per patient year), valve endocarditis 98.7 ± 1.3% (linearized rate 0.1% per patient year), and nonstructural dysfunction 90 ± 3.5% (linearized rate 1% per patient year). There was no structural deterioration. The early and long‐term results with the CarboMedics heart valve implantation were acceptable, but valve thrombosis remains a concern in the present study. Further investigation for optimal anticoagulation therapy is necessary to reduce the incidence of valve thrombosis as well as embolic and bleeding complications.
Peritoneal Dialysis in the Developing World: The Mexican Scenario
Authors: Treviño‐Becerra Alejandro , Maimone Maria Antonieta Schettino
Published: March 2003

Abstract: In the developing countries it is not possible to determine the total amount of money spent in the treatment of chronic diseases, and the practice of renal replacement therapies faces many obstacles. In Mexico, the introduction of continuous ambulatory peritoneal dialysis and continuous cycling peritoneal dialysis (CCPD) achieved very good results. Unfortunately, renal disease still affected as much as 95% of chronic renal failure patients and it became a disaster with an annual mortality rate higher than 60%. This was known as the Mexican Model which failed in establishing peritoneal dialysis as the only procedure for treating patients. In order to avoid a similar scenario with the 2 replacement therapies, we created the Official Norm for hemodialysis, and now we are experimenting with an increase from 5% to 20% of hemodialysis patients who are receiving therapy, principally in private units that attend Social Security patients. In addition, the government has established a Council for Transplantation that acts as a regulatory board. In other words, we are in the process of making chronic renal diseases a priority within the National Program.
Comorbidities in Patients with End‐Stage Renal Disease in Developing Countries
Authors: Eiam‐Ong Somchai , Sitprija Visith
Published: March 2003

Abstract: Patients with end‐stage renal disease (ESRD) who are on renal replacement therapy (RRT) usually have a certain number of comorbid factors. Cardiovascular diseases are the most common comorbidities and the most common causes of mortality in ESRD patients. Noncardiovascular comorbid factors including nutrition also have impact on survival of ESRD patients on RRT. There are scarce data regarding comorbidity in developing countries. Available data have shown that hypertension, diabetes, and various cardiovascular disorders are the leading comorbidities. Improvement in outcome for ESRD patients would depend on improving quality in RRT as well as a better understanding and management of comorbid conditions.
Titania Gel Reduces Thrombin Generation
Authors: Ishitoya Hiroshi , Kawamura Masaki , Linneweber Joerg , Motomura Tadashi , Ichikawa Seiji , Nishimura Ikuya , Glueck Julia , Shinohara Toshiyuki , Nosé Yukihiko
Published: March 2003

Abstract: Titanium alloy (Ti) commonly is used for long‐term blood pumps as a conventional blood contacting material. Thrombus formation in the pump, however, is still a critical problem. Once thrombin is generated on the Ti surface, it activates platelets and the coagulation cascade, leading to thrombus formation. It would be expected that an inhibition of thrombin generation on a blood‐contacting surface would prevent thrombus formation. In this study, the titania gel (Ti‐gel) on the surface of Ti was formed with chemical modification. The surface structure and its effects on the coagulation cascade were evaluated. Scanning electron microscopic study revealed numerous cracks on the dried surface of Ti‐gel, indicating a water‐enriched layer. Blood coagulation on the Ti‐gel was less than that on the Ti. Generated thrombin on the Ti‐gel was less than that on the Ti in both the extrinsic and intrinsic pathways. There was no statistical difference of thrombin degradation. These results suggest that coagulation cascade on the Ti surface was inhibited by the Ti‐gel formation. The Ti‐gel may have better antithrombogenic characteristics for blood pumps because of its antiblood‐coagulation effects.
Physiologic Control Algorithms for Rotary Blood Pumps Using Pressure Sensor Input
Authors: Bullister Edward , Reich Sanford , Sluetz James
Published: March 2003

Abstract: Hierarchical algorithms have been developed for enhanced physiologic control and monitoring of blood pumps using pressure inputs. Pressures were measured at pump inlet and outlet using APEX pressure sensors (APSs). The APS is a patented, long‐term implantable, flow‐through blood pressure sensor and designed to control implantable heart pumps. The algorithms have been tested using a Donavan circulatory mock‐loop setup, a generic rotary pump, and LabVIEW software. The hierarchical algorithms control pump speed using pump inlet pressure as a primary independent variable and pump outlet pressure as a secondary dependent variable. Hierarchical control algorithms based on feedback from pressure sensors can control the speed of the pump to stably maintain ventricular filling pressures and arterial pressures. Monitoring algorithms based on pressure inputs are able to approximate flow rate and hydraulic power for the pump and the left ventricle.
Collagen‐Hydroxyapatite Microspheres as Carriers for Bone Morphogenic Protein‐4
Authors: Wang Yng‐Jiin , Lin Feng‐Huei , Sun Jui‐Sheng , Huang Yi‐Chau , Chueh Shan‐Chang , Hsu Fu‐Yin
Published: March 2003

Abstract: The purpose of the current study is to evaluate the carrier capability of collagen‐hydroxyapatite microspheres to the bone morphogenic proteins (BMP). After anesthesia, a bone defect (6.0 mm in diameter and 10.0 mm in depth) was created at the distal femoral condyles of New Zealand white rabbits. These 10.0 mm3 defects were then completely filled with the implant materials. After 2, 4, 6, and 8 weeks, the animals were sacrificed and histological evaluations were performed. The results showed that when the defects were left untreated, there was no evidence of bone formation during the eight‐week experimental period. In the group treated with collagen‐hydroxyapatite microspheres without BMP‐4, the defect was filled with fibrous tissue and inflammatory cells, while active bone formation with mature marrow tissue formation was evident in the defect treated with collagen‐hydroxyapatite microspheres containing BMP‐4. Collagen‐hydroxyapatite microspheres were expected to be replaced by the regenerated bone structure as the bone reconstruction and bone remodelling process occurred. It was apparent that bone regeneration was influenced by the addition of BMP‐4. Collagen‐hydroxyapatite microspheres were good carriers for bone morphogenic proteins.
A Concept of Integrated Water Management Illustrated for Flanders (Belgium)
Authors: Schneiders Anik , Verheyen Rudi
Published: March 2003

ABSTRACT

Integrated catchment management (ICM) is an application of the concept of sustainable development for aquatic ecosystems. It aims at developing, maintaining, and restoring the water system to reach the quality objectives of multifunctional use for this generation without compromising the uses for future generations. The quality objectives should be based on sufficient ecosystem knowledge. ICM demands a solid and workable framework built on the integration of knowledge and organizational integration which are supported by statutory rules and (international) regulations. In Flanders, future legal support will be based on both the framework for water action plans proposed by the European Commission, and a Flemish decree concerning integrated water management. The overview given for ecosystem knowledge is (on a Flemish scale) based on data networks. The interrelation and processing of large data sets deliver basic knowledge to build up policy visions for land‐use planning and environmental planning. Organizational integration will be worked out on two levels: an Integrated Water Consultation Committee on a Flemish level (13,806 km2) will work out the outlines and examine the sector‐oriented long‐term demand for water; and Catchment Committees on a subbasin level (scale: 700–2300 km2) will bring together the relevant parties and work out integrated catchment plans (ICP). Bringing together the administrations of Environmental Planning and Town and Country Planning around one vision, with a balanced multifunctional use, is one of the biggest challenges of ICP in Flanders.
Staying Out of the Lifeboat: Sustainability, Culture, and the Thermodynamics of Symbiosis
Authors: Peacock Kent
Published: March 2003

ABSTRACTMany authors state that sustainability is purely a matter of the management of scarce and ever‐diminishing “negentropy,” while others still pretend that unlimited exploitation of the environment is possible. Either view rests on fundamental misunderstandings of ecosystems. Ecologically, sustainability must mean a mutualistic symbiosis. It is useful to understand symbiosis from a thermodynamic point of view. Many organisms—including humans in principle—are able tomodulatelarge flows of free energy, directing it into the formation of organized structures, while expending a proportionately small amount of free energy in the process. They are thus able to capture useful energy for their ecosystem as a whole. Ecosystems can thus maintain a high degree of internal coherence and, just as can individual organisms, apparently defy the Second Law of Thermodynamics within their own boundaries. The breakdown of ecosystem coherence we observe in the world today is thus a symptom not so much of the “Law of Entropy” but of the undermining of the ecosystem’s autopoietic capacity by human parasitism. A guarded optimism about the possibility of sustainability is thus possible, so long as we grasp the particular way in which humans can contribute to ecosystem vitality. Even very subtle features of human culture may contribute positively to the physical vitality of the ecosystem.
The Effect of Sumatriptan on Brain Monoamines in Rats
Authors: Mitsikostas D.D. , Papadopoulou‐Daifotis Z. , Sfikakis A. , Varonos D.
Published: March 2003

Clinical data suggests that sumatriptan is effective in the acute treatment of migraine. The vascular sumatriptan on brain monoamines has not previously been investigated. In order to study these and 0.9 mg/kg of body weight), and 30 minutes later, all animals were decapitated Dopamine, serotonin, concentrations were measured in the frontal cortex, hypothalamus, striatum, and hippocampus, by high performance liquid chromatography. Plasm group was treated with NaCl 0.9%, given subcutaneously.

Sumatriptan, at the dose of 0.3 mg/kg did not alter the brain monoamine concentrations; however, at the turnover of dopamine and serotonin in the hypothalamus and striatum, while at the dose of 0.9 mg/kg, found. This subcortical antidopaminergic and antiserotoninergic effect of sumatriptan may be involved in its antimigraine action.
Meningeal Hyperperfusion Visualized by MRI in a Patient With Visual Hallucinations and Migraine
Authors: Lindner Alfred , Reiners Karlheinz , Toyka Klaus V.
Published: March 2003

A 41‐year‐old patient with a history of migraine but with no history of seizures had intermittent prolonged and variable complex visual hallucinations and illusions lasting 9 days, accompanied by unilateral headache. Electroencephalography during these visual symptoms revealed occipital epileptic discharges. Distinction between focal migrainous attacks and ictal phenomena was difficult. Magnetic resonance imaging showed a lesion in the right visual cortex probably related to low perfusion and hyperemia of meningeal vessels, representing the rarely described transient MRI changes associated with migraine. Continued treatment with antiepileptic drugs and calcium‐channel blocking agents completely resolved the headache and visual symptoms, while minor EEG changes persisted. After discontinuation of treatment, a second attack occurred with a similar and reversible pattern on EEG.
Magnetic Resonance Imaging for Recurrent Headache in Childhood and Adolescence
Authors: Wöber‐Bingöl Cicek , Wöber Christian , Prayer Daniela , Wagner‐Ennsgraber Christa , Karwautz Andreas , Vesely Christine , Zebenholzer Karin , Feucht Martha
Published: March 2003

We investigated 429 consecutive patients, aged 5 to 18 (mean: 11.0 ± 3.1) years, diagnosed with migraine or tension‐type headache. The patients underwent either MRI or exclusively clinical follow‐up examinations. Magnetic resonance imaging revealed normal findings in 82.3% and structural changes in 17.7%. However, the vast majority of these changes had minimal or no pathological relevance, and a causal relationship to the patient’s headache could not be proven in any case. In the non‐MRI group, clinical follow‐up examinations confirmed the initial diagnosis in all patients and MRI was not required in any of these subjects. In conclusion, our study shows a poor relation between recurrent headache fulfilling the criteria of migraine and tension‐type headache and structural changes incidentally detected by MRI. In addition, it suggests that clinical follow‐up examinations are reliable. Accordingly, MRI is not required for routine examination of recurrent headache in children and adolescents, but it should be performed in patients with abnormal neurological findings, atypical headache pattern, or significant change of preexisting headache.
Severe Barbiturate Withdrawal Syndrome in Migrainous Patients
Authors: Raja Michele , Altavista Maria Concetta , Azzoni Antonella , Albanese Alberto
Published: March 2003

Three patients who presented with grand real seizures and an associated behavioral disorder were recognized as suffering from a severe butalbital withdrawal syndrome. All were migraineurs who had become dependent on barbiturates. We propose that the occurrence of seizures, psychotic behavior, or a recent personality change should be considered clues to possible barbiturate abuse in patients with migraine.
SUNCT Syndrome: Duration, Frequency, and Temporal Distribution of Attacks
Authors: Pareja Juan A. , Shen Jie Ming , Kruszewski Piotr , Caballero Vicente , Pamo Manuel , Sjaastad Ottar
Published: March 2003

Duration, frequency, and temporal distribution of attacks have been objectively estimated in 11 SUNCT patients (3 women and 8 men). The mean age at the time of the study was 69 years (range 52 to 81). The duration of a total of 348 attacks was measured from videotape records, polygraphic tracings, or by stopwatch.The duration of attacks ranged from 5 to 250 seconds, with an unweighted mean of 61 seconds. Both frequency and exact timing of attacks were assessed in four patients who filled in a time chart with the exact onset of 585 consecutive attacks. The majority of attacks occurred during daytime, with a bimodal distribution; ie, morning and afternoon/evening peaks, and only a few attacks were noted at night (ie, 1.2% of the attacks). The unweighted mean frequency of attacks was 28 per day (range 6 to 77).

Duration and timing of attacks in SUNCT syndrome may be of help in the differential diagnosis versus other disorders with the same localization, especially first division trigeminal neuralgia.
The Epidemiology of Migraine in Medical Students
Authors: Sanvito Wilson Luiz , Monzillo Paulo Hélio , Prieto Peres Mário Fernando , Martinelli Mauro Olivio , Fera Melissa Patrick , da Cruz Gouveia Daniela Alves , Murachovsky Joel , dos Santos Salomão Wilson Roberto , de Almeida Leme Ricardo José
Published: March 2003

The purpose of this study was to investigate the prevalence of migraine in medical students, as well as its clinical aspects and impact. All 595 medical students of Santa Casa School of Medicine of São Paulo, Brazil were asked if they had experienced any kind of headache in the past year. Those who responded positively were further investigated by an appropriate questionnaire. Diagnosis of migraine was based on the International Headache Society criteria of 1988. Forty percent of students suffered from some kind of headache; 40.2% of these headaches were migraine. The prevalence of migraine was 54.4% in women and 28.3% in men. Migraine headaches were unilateral in 24.2%, had a gradual onset in 69%, and were of a throbbing type in 88.3%. Migraine was considered incapacitating by 53.9% of students. Migraine with aura caused more disability than migraine without aura. Women experienced more intense migraine than men, and migraine with aura was especially more severe than migraine without aura. Photophobia, phonophobia, and nausea were more commonly encountered in migraine with aura. Despite the high prevalence, the high rate of disability, and the need for analgesic medication, only 7.1% of students with migraine had sought medical treatment.
The Role of Cranial Computed Tomography in the Diagnostic Work‐up of Headache
Authors: Demaerel Philippe , Boelaert Ignace , Wilms Guy , Baert Albert L.
Published: March 2003

Approximately 18% of all patients referred for a cranial computed tomography complain of headache only.

We reviewed 363 consecutive patients in order to assess the value of this examination in the diagnostic approach.

Despite the vast number of normal examinations (88.4%), we advocate the routine use of a cranial computed tomography in every patient with chronic headache. The cost of the examination can significantly be reduced by performing an unenhanced scan only. An additional contrast‐enhanced scan should be obtained if a suspicious lesion is seen. Brain magnetic resonance imaging is not indicated except in the preoperative workup of a lesion visualized on computed tomography.
A Community‐Based Prevalence :Study on Headache in Malaysia
Authors: Alders E.E.A. , Hentzen A. , Tan C.T.
Published: March 2003

This community study on headache in Malaysia was based on IHS diagnostic criteria and showed the last‐year prevalence of migraine was 9.0%. Migraine with aura accounted for only 10.6% of the migrainous population. The last‐year prevalence of tension headache was 26.5% (94.4% episodic, 5.6% chronic) and 28.2% for other types of headache. No case of cluster headache was found. Almost two thirds of the migraine subjects graded their headaches as severe, while almost 60% of the tension headache subjects and almost 70% of the other headache subjects graded their headaches as mild.

Overall, there was higher prevalence in females for migraine and tension headache, and in males for the other types of headache. The prevalence of headache was lower among those younger than 15 and older than 65 years of age. No significant differences were found in the prevalence of headache among the different racial groups nor among the urban versus the rural population.

All the headache types shared the same triggering factors suggesting that different physiological characteristics are responsible for the type of pain suffered. In the location of this community with its tropical climate, headache was attributed to sun exposure in 51.9% of the migraine subjects, 55.7% of the tension headache subjects, and 36.6% of the group with other headaches.
Increasing Prevalence of Headache in 7‐Year‐Old Schoolchildren
Authors: Sillanpää Matti , Anttila Pirjo
Published: March 2003

Reports of increased prevalence of headache in adults end clinical impressions of similar trends in children prompted this epidemiological study on migraine and other headache. The first stage was carried out in 1974 In children starting school, and the second stage in 1992 using the identical study design, the same age group, and a similar urban child population.

The overall prevalence of present headache (having occurred in the previous 6 months) was found to he significantly increased over time, from 14.4% in 1974 to 51.5% in 1992. Similarly, the prevalence of migraine headache had Increased from 1.9% to 5.7%. The causes of the increase are as yet unknown. The highest but not significant increases were found in schools which were situated in the districts of the city with the highest social instability, which was reflected in the high percentage of council houses and also in the higher frequency of family relocations. Increase over time in the prevalence of migraine end other headaches in children pears to be at least as dear as in adults. This should alarm the community to study the underlying stress factors and to try to relieve the children’s distress.
Sympathetic Vasoconstrictor Outflow to Extremity Muscles in Cluster Headache. Recordings During Spontaneous and Nitroglycerin‐Induced Attacks
Authors: Nordin Magnus , Fagius Jan , Waldenlind Elisabet
Published: March 2003

To search for evidence of sympathetic dysregulation during cluster headache attacks, microneurographic recordings of muscle nerve sympathetic activity (MSA) were obtained from the peroneal nerve.

In three recordings commenced after the onset of spontaneous attacks, MSA was about twice as high during the attack as afterwards. In four nitroglycerin‐induced attacks, MSA showed a rise paralleling the pain, preceded by an initial peak. The latter accompanied hypotension, whereas the rise coinciding with cluster headache was associated with rising blood pressure. The normal baroreflex‐governed pulse synchrony of MSA was preserved both during spontaneous and provoked attacks. In seven cluster headache patients in whom nitroglycerin did not cause an attack, only an initial peak in MSA occurred. Nor was any late nitroglycerin‐induced rise in MSA observed in nine healthy subjects; the initial peak in MSA and heart rate was followed by a rapid return to normal despite a falling blood pressure.

It is concluded that cluster headache attacks are associated with an increase in MSA that elevates blood pressure by causing vasoconstriction, and that this increase, rather than indicating sympathetic dysregulation, is a normal pain. evoked secondary phenomenon. The findings in healthy subjects support the notion that nitroglycerin has a central sympatho‐inhibitory effect.
Migrainelike Headache in a Patient With a Hemorrhagic Pituitary Macroadenoma
Authors: Evans Randolph W.
Published: March 2003

A 23‐year‐old woman presented with a 4‐day history of a severe migrainelike headache with a normal neurologica examination. The headache resolved after a ketorolac injection, but recurred a few hours later. An MRI scan of the brain showed a hemorrhagic pituitary macroadenoma for which she underwent transsphenoidal removal of the tumor 1 month later. Although uncommon, pituitary hemorrhage with and without apoplexy should be considered in the differential diagnosis of acute headache. Pituitary hemorrhage can be routinely identified on an MRI scan even without pituitary views. However, the pathology can be overlooked and underimaged on a CT scan for acute headache using 10‐mm and even 5‐mm slices.
Involvement of a Ca 2+ Channel Gene in Familial Hemiplegic Migraine and Migraine With and Without Aura
Authors: Ophoff Roel A. , Terwindt Gisela M. , Vergouwe Monique N. , Frants Rune R. , Ferrari Michel D. ,   Dutch Migraine Genetics Research Group
Published: March 2003

A gene for familial hemiplegic migraine, a subtype of migraine with aura, was assigned to chromosome 19p13. In this region, we identified a brain‐specific P/Q‐type calcium channel α1a‐subunit gene, CACNA1A, with 47 exons covering 300 kb. Sequencing of all exons and their flanking surroundings revealed polymorphic variations, including a (CA)0‐repeat anti a (CAG)n‐repeat in the 34 untranslated region. In patients with familial hemiplegic migraine, we found four different missense mutations in conserved functional domains. One of the mutations has occurred on two different haplotypes in unrelated familial hemiplegic migraine families. Moreover, in episodic ataxia type 2, we found two mutations disrupting the reading frame. Thus, familial hemiplegic migraine and episodic ataxia type 2 can be considered as allelic channelopathies. Involvement of this familial hemiplegic migraine locus in migraine with and without aura was demonstrated by sib‐pair analysis. We showed an increase of shared marker alleles of locus D19S394, which is tightly linked to the gene. The association between the α1A calcium channel and familial hemiplegic migraine, and the increase of shared alleles in migraine‐affected sib‐pairs, have uncovered a new pathway for the pathophysiology of migraine. This finding may provide a rationale for the development of specific prophylactic therapy for migraine and other (paroxysmal) cerebral disorders.
Migraine and Stress: A Daily Examination of Temporal Relationships in Women Migraineurs
Authors: Holm Jeffrey E. , Lokken Cami , Myers Tricia Cook
Published: March 2003

This study examined daily temporal relationships between stress, cognitive appraisal, coping, and migraine in a group of young women migraineurs sampled from a general population. Participants (N=20) meeting International Headache Society 1 criteria for migraine with or migraine without aura provided headache activity, perceived stress, cognitive appraisal, and coping strategy data across 2 months of data collection. A time‐series analytic approach was used to cross‐correlate daily stress, appraisal, and coping data with daily headache data controlling for factors that can inflate correlations in data collected across time. Analyses revealed that between 50% and 70% of subjects showed significant, substantial, and meaningful temporal correlations between their daily stress and their daily migraine activity. Furthermore, these data support the hypothesis that stress and migraine are reciprocally related (ie, cyclically influencing each other across time). In addition, despite some measurement concerns, our data suggest that cognitive appraisal and coping are also related to migraine activity in a reciprocal fashion.
Sumatriptan Injection and Tablets in Clinical Practice: Results of a Survey of 707 Migraineurs
Authors: Dahlöf Carl G.H. , Saiers Jane
Published: March 2003

This report from the Gothenburg Migraine Clinic in Sweden describes the results of a telephone survey of over 700 patients using open‐label sumatriptan tablets or sumatriptan injection for the treatment of migraine. The information is based on the patients' cumulative experience of more than 76 000 subcutaneous injections, 56 000 tablets 100 mg, and 20 000 tablets 50 mg. The results demonstrate that sumatriptan tablets were preferred by a greater proportion of patients than sumatriptan injection. However, sumatriptan injection was perceived as the most effective dosing form by the greatest proportion of patients. Among patients who found sumatriptan injection to be the most effective dosing form, the most frequently cited reasons were efficacy and speed of action. Among patients who found sumatriptan tablets to be the most effective dosing form, the most frequently cited reasons were fewer side effects and lack of experience with other dosing forms. Approximately half of sumatriptan users indicated that sumatriptan use was associated with decreases in the numbers of days with migraine, days at work with migraine, and days off work/normal activities due to migraine. When they worked during a migraine attack, patients estimated that they were 76% effective after taking sumatriptan compared with 47% effective with other medications and 49% effective with no medication. In general, side effects were reported less frequently among sumatriptan tablet users compared with injection users. Asked to compare sumatriptan with the best migraine treatment that they had used before, 94% of patients indicated that sumatriptan was better or much better than their previous therapies. These data provide important information from the clinical practice setting to complement the data from sumatriptan clinical trials.