bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk Factors for Pain After Mastectomy/Lumpectomy
Authors: Carpenter Janet S. , Sloan Paul , Andrykowski Michael A. , McGrath Patrick , Sloan David , Rexford Tracy , Kenady Daniel
Published: March 2003

purpose
: Careful study of risk factors that predispose an individual to developing postmastectomy pain (PMP) after breast cancer surgery has not been reported. This study examined potential risk factors for PMP including demographic, disease, and treatment variables, as well as surgical factors, such as surgical technique and number of lymph nodes removed.

description of the study
: Data were collected via telephone interviews and review of medical records. Pain was assessed using the Brief Pain Inventory. The sample included 134 breast cancer survivors who were a mean age of 55 years (SD = 9) and a mean of 35 months postsurgery (SD = 19).

results
: Women with PMP (n = 36) were not significantly different from women without PMP (n = 98) on demographic, disease, treatment, or surgical variables. PMP intensity was not significantly associated with age at diagnosis, time postsurgery, or time post‐treatment. Contrary to expectation, PMP was found in women postlumpectomy without axillary dissection, women whose intercostobrachial nerve was spared, and women without documented postoperative complications.

clinical implications
: Findings suggest that cases of PMP cannot uniformly be identified based on the presence or absence of certain factors. Findings also underscore the need to screen all women for PMP after breast cancer surgery, particularly given the availability of effective pain management therapies.
Premature Menopause After Cancer Treatment
Authors: Muscari Lin Esther , Aikin Jennifer L. , Good Barbara C.
Published: March 2003

purpose
: The purpose of this report is to examine the impact that cancer therapies have on ovarian function.

overview
: Symptoms of and conditions due to estrogen deficiency after cancer therapy are described, and interventions are proposed. The consequences of short‐term as well as prolonged estrogen deficiency—including vasomotor instability, infertility, genitourinary atrophy, coronary artery disease, and osteoporosis—are discussed.

clinical implications
: Symptoms and conditions associated with premature menopause may cause additional stress for women who undergo cancer therapy. Knowledge about what happens to these women can enable healthcare providers to help them make decisions about cancer treatment, engage in self‐care activities, and explore options for preserving fertility.
Findings from an Educational Support Course for Patients with Leukemia
Authors: McGrath Pam
Published: March 2003

objectives: Recent evidence indicates that patients with leukemia are a distinct subset of cancer patients with specific adjustment issues and special needs for support and follow‐up. This article shares recent research findings on an Australian educational support course, appropriately named Taking Control, designed specifically for patients with leukemia and associated disorders.

materials and methods: The material presented in this article represents the findings from the retrospective arm of a descriptive study designed to evaluate this course. Participants in the course during the calendar year of 1997 were surveyed with an author‐designed, self‐report questionnaire requesting feedback on their experience of the course.

results: Although the majority of participants were seeking information, there was strong evidence that the provision of information needs to be coupled with an understanding of the psychosocial reasons that motivated individuals to attend the course. The findings indicate that the course is perceived by participants to be an effective psychosocial intervention for assisting patients and their families cope with the serious diagnosis of leukemia.

conclusions: Even though information seeking was an important reason for attending this educational course, there were many other significant emotional concerns that individuals brought to the experience. When exposed to the stress of leukemia and its treatment, patients and their significant others may become preoccupied with information gathering. Therefore, it is important to not only explore the issue of the informational needs of participants, but also to examine the emotional needs they associate with this information gathering. The hope and expectation about sharing the findings of this program is that it will assist with the development of similar programs elsewhere and will stimulate further research on the importance of educational support groups in oncology.
Screening Mammography for Elderly Women
Authors: Johs‐Artisensi Jennifer , McGill Jerry
Published: March 2003

Purpose: Breast cancer is one of the most common and deadly cancers among elderly women, but there is little consensus in the literature about appropriate screening guidelines for the elderly. In this report, evidence‐based studies addressing the efficacy and effectiveness of mammography screening programs for elderly women are analyzed and interpreted.

Overview: Although there is little direct scientific evidence to support (or to disavow) the benefits of mammography screening for elderly women, a review of the relevant literature supports the benefits of screening mammography for this population. The authors believe that the current evidence supports the efficacy and effectiveness of mammography screening programs for women up to at least age 80 and also suggests that women older than age 80 who are in good general health will also benefit from screening.

Clinical implications: Most individuals rely on their healthcare providers' recommendations to aid them in making decisions regarding their health. When healthcare professionals are equipped with evidence‐supported guidelines, they can ensure that appropriate recommendations are being made for their patients. Healthcare professionals who treat the elderly should implement the authors' recommendations, supported by current evidence. The lack of direct evidence should not be interpreted as evidence against the use of screening mammography for the elderly but rather as a call for clinical research on preventive healthcare for senior citizens.
Lake Superior Rural Cancer Care Project
Authors: Elliott Thomas E. , Elliott Barbara A. , Regal Ronald R. , Renier Colleen M. , Haller Irina V. , Crouse Byron J. , Witrak Martha T. , Jensen Patricia B.
Published: March 2003

purpose: Effective methods that encourage rural primary‐care physicians to adopt state‐of‐the‐art cancer‐management practices are needed. The purpose of this study was to evaluate educational and systems strategies to improve rural primary‐care physicians' cancer practice behaviors.

description of study: The Lake Superior Rural Cancer Care Project was a group‐randomized, controlled trial conducted with 18 rural communities in the North Central United States over 4 years. Although the unit of analysis was the community, the subjects were 104 primary‐care physicians and 2089 rural patients with cancer. The intervention was educational and comprised systems strategies that targeted rural primary‐care physicians and their healthcare delivery systems. The outcome measures reported here were physician practice behaviors regarding cancer diagnosis, staging, treatment, clinical trial participation, and post‐treatment surveillance.

results: The intervention significantly improved 5 of the 37 cancer practice end points. The overall result of the study did not support the majority of the study hypotheses. Because 16 practice end points were found to be at acceptable performance levels, the possibility of a measurable intervention effect was limited.

clinical implications: Earlier, the authors reported the results of the intervention on providers' cancer management knowledge, which showed significant improvement. The present study findings demonstrated that improving provider knowledge does not necessarily improve practice performance. Changing practice behaviors requires much more effort. Furthermore, interventions found to be effective in other diseases, types of providers, or settings may not work on rural providers for cancer management.
Exercise Counseling and Programming Preferences of Cancer Survivors
Authors: Jones Lee W. , Courneya Kerry S.
Published: March 2003

purpose: Exercise has emerged as an important quality‐of‐life intervention for cancer survivors, but exercise motivation is a challenge. The purpose of this study was to provide a comprehensive assessment of the exercise preferences of cancer survivors.

description of study: A mailed, self‐administered survey was completed by 307 survivors of prostate, breast, colorectal, or lung cancer. The survey contained questions on demographic and medical variables, past exercise, and various exercise counseling and programming preferences.

results: For exercise counseling, 84% of participants said they preferred or maybe preferred to receive exercise counseling at some point during their cancer experience. Moreover, 85% preferred to receive exercise counseling face to face, and 77% preferred to receive it from an exercise specialist affiliated with a cancer center. For exercise programming, 98% preferred recreational exercises, 8!% preferred walking, 57% preferred unsupervised exercise (57%), and 56% preferred moderate‐intensity exercise. In addition, 48% preferred to exercise in the morning, 44% preferred to exercise alone, 40% preferred to exercise at home, and 32% preferred to start their exercise program before treatment. Chi‐square analyses revealed that a small number of exercise preferences were moderated by demographic, medical, and exercise variables.

clinical implications: The results of this study indicate that cancer survivors have unique and varied exercise counseling and programming preferences. Fifty‐six percent of cancer survivors preferred to exercise at moderate intensity rather than at high intensity. Moderate‐intensity exercise has been shown previously to be relatively safe even for cancer survivors who are advanced in age. The key to success for inactive cancer survivors may be to provide reassurance that exercise is a safe and beneficial modality for cancer survivors and to prescribe an exercise program that builds their confidence by slowly increasing the level of exercise intensity.
Holomeric vs. meromeric segmentation: a tale of centipedes, leeches, and rhombomeres
Authors: Minelli Alessandro
Published: March 2003

SUMMARY Explaining the origin and evolution of segmentation is central to understanding the body plan of major animal groups such as arthropods, annelids, and vertebrates. One major shortcoming of current views on segmentation is the failure to recognize the existence of two layers of segmentation. I distinguish here holomeric segmentation, involving the whole body axis (or the whole axis of an appendage) and producing “ true” segments (eosegments); and meromeric segmentation, producing merosegments within one or more eosegment(s). In terms of developmental mechanisms, meromeric segmentation is probably the same as compartmentalization. This process follows two rules: (1) merosegments are formed from a stereotyped pattern of subdivisions, where only the merosegments in contact to the anterior or posterior boundary of the eosegment are allowed to divide; (2) contiguous eosegments undergoing meromeric segmentation generate merosegments according to identical lineage patterns apart from possible lineage truncation in one or a few terminal eosegments. The segmentation model proposed in this paper is mainly supported by evidence from comparative morphology, but it is compatible with known cellular and developmental mechanisms. The development of vertebrate rhombomeres, the annulation of leeches, the subdivision of the distal part of insect antenna into flagellomeres and the segmentation of centipedes are interpreted here in terms of meromeric segmentation. Some of these phenomena, like centipede segmentation, have thus far defied all attempts at an explanation, both in mechanistic (developmental) and phylogenetic terms. The model presented in this paper suggests a rich research agenda at all levels, from molecular and genetic to morphological and phylogenetic.
Modeling the maternal‐age dependency of reproductive failure and genetic fitness
Authors: Zheng Chang‐Jiang , Guo Sun‐Wei , Byers Breck
Published: March 2003

SUMMARY The offspring of older parents are at a higher risk of suffering low birth weights and congenital birth defects that result from mutations and chromosomal anomalies. When the defect is paternal in origin, it often can be shown that the primary lesion arose during mitotic proliferation of the spermatogonial germ cell population. By contrast, germline mosaicism is seldom invoked to explain the age dependency of maternally derived aberrations because germline proliferation in the ovary is already completed during fetal development. Age‐dependent defects of maternal origin might, however, be explained in part by the progressive loss of oocytes during the mother's reproductive life. A large number of oocytes undergo the initial stages of maturation each month, but typically only one completes maturation and is ovulated while the majority are discarded, probably by an apoptotic mechanism. Here we explore the possibility that the monthly choice of oocytes to undergo maturation is influenced by subtle phenotypic characters of those oocytes that may bear genetic defects such as trisomy 21. We have generated a mathematical model to describe the loss kinetics for such mutant oocytes relative to the overall pool of resting oocytes, and we assess evolutionary strategies that would favor their utilization faster than, at the same rate as, or slower than the normal oocytes. This formulation reveals that the slower‐rate scheme would effectively diminish the utilization of mutant oocytes in young mothers but would increase the risk of related birth defects for older mothers. Accordingly, we propose that natural selection should have favored the delayed utilization of defective oocytes in a primitive high‐mortality culture, but that this evolutionary strategy would be outmoded for modern society, because it would lead to an increased frequency of birth defects for older mothers.
The gene is not dead, merely orphaned and seeking a home
Authors: Hall Brian K.
Published: March 2003

SUMMARY Despite announcements and obituaries, news of the death of the gene has been greatly exaggerated, or so says the gene as it struggles to survive and find a safe haven from which to steer its course through development and evolution. In this short piece, I consider recent claims that the gene is dead. I conclude that the gene is alive and well, living and functioning in the cell, which is both its natural home and a fundamental unit of evo‐devo.
Evolution of the echinoderm Hox gene cluster
Authors: Long Suzanne , Byrne Maria
Published: March 2003

SUMMARY

Extant echinoderms are members of an ancient and highly derived deuterostome phylum. The composition and arrangement of their Hox gene clusters are consequently of interest not only from the perspective of evolution of development, but also in terms of metazoan phylogeny and body plan evolution. Over the last decade numerous workers have reported partial Hox gene sequences from a variety of echinoderms. In this paper we used a combined methods approach to analyze phylogenetic relationships between 68 echinoderm Hox homeodomain fragments, from species of five extant classes—two asteroids, one crinoid, one ophiuroid, one holothuroid, and three echinoids. This analysis strengthens Mito and Endo's (2000) proposition that the ancestral echinoderm's Hox gene cluster contained at least eleven genes, including at least four posterior paralogous group genes. However, representatives of all paralogous groups are not known from all echinoderm classes. In particular, these data suggest that echinoids may have lost a posterior group Hox gene subsequent to the divergence of the echinoderm classes. Evolution of the highly derived echinoderm body plan may have been accompanied by class‐specific duplication, diversification and loss of Hox genes.
Evolutionary implications of developmental instability in parthenogenetic Drosophila mercatorum. I. Comparison of several strains with different genotypes
Authors: Kramer Melissa G. , Templeton Alan R. , Miller Kathryn G.
Published: March 2003

SUMMARY Natural populations of sexually reproducing Drosophila mercatorum are capable of a very low rate of parthenogenesis, but this mode of reproduction has apparently never characterized an entirely asexual population in this species. The high abortion rate observed in laboratory parthenogenetic lines suggests that developmental constraints may cause the failure of this trait to spread in nature. To investigate the basis of this developmental instability and how it may affect the evolution of parthenogenesis in natural populations, early embryonic development was compared between one sexual and four parthenogenetic laboratory strains of D. mercatorum. There is a large amount of variation within a given parthenogenetic strain, suggesting that parthenogenesis is associated with a general breakdown of developmental stability. There is relatively little variation among different parthenogenetic strains, suggesting that most abortions are due to a feature inherent to parthenogenetic reproduction rather than a feature of a particular genome. Likewise, there is little variation between parthenogenetic and sexual strains in the causes of abortions, suggesting that the developmental problems encountered by parthenogenetic lineages are not unique to parthenogens. Thus, the failure of parthenogenesis to spread within D. mercatorum can be attributed to no particular developmental constraint per se operating after the initiation of embryogenesis. However, the overall increase in all developmental problems that occurs with the transition from sexual to parthenogenetic development suggests that the high degree of developmental instability associated with parthenogenesis may be considered a developmental constraint in its own right.
Implantable Micropump System for Augmented Liver Perfusion
Authors: Marseille Oliver , Habib Nagy , Reul Helmut , Rau Günter
Published: March 2003

Liver cirrhosis, a worldwide health problem, decreases the blood flow through the liver. This in turn leads to dangerous portal hypertension and decreased metabolic function within the liver. To improve this situation, a new concept is proposed which involves introducing a microaxial blood pump into the portal vein. This device is intended to increase blood flow through the liver and to enhance hepatic function. Furthermore, high pressures will be reduced to physiological levels. The microaxial pump with its single stage impeller is powered by a proximally integrated microelectric motor. The pump unit is completely immersed within the blood vessel. Heat caused by electrical and mechanical losses will be transported into the blood. In vitro optimization of the pump design was accomplished using both hydraulic and hemolysis tests.
A Continuous and Pulsatile Flow Circulation System for Evaluation of Cardiovascular Devices
Authors: Vermette Patrick , Thibault Jules , Laroche Gaétan
Published: March 2003

The design of a nonpulsatile and pulsatile system using a centrifugal pump is presented. To induce a pulsatile flow with a centrifugal pump, an independent pneumatically driven unit provided flow patterns over a wide range of frequencies and amplitudes. The pulsatile flow was generated by the axial displacement of a cylinder that periodically compressed the flexible conduit that is connected to the pump. The system can accommodate flow rates up to 6,000 ml/min and transmural pressures up to 500 mm Hg and is capable of maintaining the pressure at a constant value. This circuit produced reproducible pressure waves having a frequency up to 4 Hz. The periodicity of the transmural pressure between 80 and 180 mm Hg was similar to the pressure wave propagation observed in peripheral circulation. Capable of adequately reproducing continuous and pulsatile flow, the apparatus is therefore versatile to allow in vitro evaluation of cardiovascular devices.
Fine Trabecularized Carbon: Ideal Material and Texture for Percutaneous Device System of Permanent Left Ventricular Assist Device
Authors: Tagusari Osamu , Yamazaki Kenji , Litwak Philip , Kojima Akira , Klein Edwin C. , Antaki James F. , Watach Mary , Gordon Lisa M. , Kono Kunihisa , Mori Toshio , Koyanagi Hitoshi , Griffith Bartley P. , Kormos Robert L.
Published: March 2003

The development of a percutaneous artificial internal organ system requires a reliable biocompatible connection between the external environment and the inside of the human body. Such is necessary for the success of a permanent left ventricular assist device. However, the search for a satisfactory interface at the epidermal level has proven to be difficult. Carbon has been proposed for this application, but its texture does not typically promote ingrowth from surrounding tissue. We have therefore employed a new processing method to produce a fine trabecularized carbon implant. The method for preparing the implant involves infiltrating low temperature pyrolytic carbon into the surface of a carbon core which is wrapped with carbon fabric. This results in a tightly woven porous structure of carbon (carbon fiber diameter: 35–50 μm, maximal pore size > 200 μm) with gradually increasing porosity from 15–75%. We implanted test samples percutaneously in a calf for in vivo histological evaluation. Thirty days after implantation epidermal downgrowth was minimal. Microscopic analysis revealed that a thin fibrous capsule surrounded the implant, and mature connective tissue with accompanying blood vessels filled the pores of the fine trabecularized carbon layer. From these results we suggest that fine trabecularized carbon is ideally suited for a percutaneous device system in a permanent left ventricular assist device.
A New Approach to Evaluate Vascular Access in HemodialysisPatients
Authors: Bouchouareb Dammar , Saveanu Adriana , Bartoli Jean Michel , Olmer Michel
Published: March 2003

Abstract: We evaluated the importance of vascular access in hemodialysis patients using noninvasive methods with the Transonic Systems monitor in 108 patients. Most of these patients (84%) had native vein fistulas. We found that a blood flow rate of below 500 ml/min suggested the occurrence of vascular stenosis and justified confirmation by angiography. Increased recirculation could be evaluated readily and was detected in only 10% of patients. Finally, employing the evaluation of the Kt/V index, we found a good correlation between low flux through the fistula and a low Kt/V value.
Estimation of Mass Transfer Through a Hemodialyzer: Theoretical Approach and Clinical Applications
Authors: Petitclerc Thierry
Published: March 2003

Abstract: The estimation of the solute mass transfer through a dialyzer is generally based on the solute dialysance, but the concept of dialysance has been precisely defined only in the case of a merely diffusive transfer. In actuality the mass transfer of a solute is also influenced by the ultrafiltration responsible for a convective transfer and, if the solute is an ionic substance, by the transmembrane gradient of electrical potential due to the Gibbs‐Donnan effect. The aim of this paper is to generalize the concept of dialysance when the diffusive, convective, and electric components of the transfer are simultaneously active. There are at least 3 modes to generalize the concept of dialysance for it to be identical, when the amount of ultrafiltration and the Gibbs‐Donnan effect are negligible, to the usual dialysance defined in the case of a merely diffusive transfer. The dialysance can be defined so that it can be equal to the clearance for a solute absent from the dialysate again, so that it still represents the rate at which the plasma concentration of a given solute is reaching its equilibrium value, or so that it represents the merely diffusive component (independent of the ultrafiltration rate) of the mass transfer. This generalized concept of dialysance can be useful to provide a real‐time estimation of the effective dialysis dose actually delivered to the patient; to automatically optimize, by a biofeedback process, the sodium balance during a hemodialysis session; and to adapt dialysate concentrations for new hemodialysis techniques with convective transfer (acetate‐free biofiltration).
History of the Kolff Laboratory Turbine Driven Electrohydraulic Artificial Heart
Authors: Topaz Stephen R. , Flinders Thom , Topaz Howard A. , Jones David
Published: March 2003

The concept of an electrically powered total artificial heart has been pursued by Dr. Kolff and his associates since the 1960s. Since the 1980s these efforts have been concentrated upon the development of the electrohydraulic total artificial heart, a turbine pump powered by a brushless DC motor. Dr. Kolff realized the benefits of pulsatile flow and device response to Starling's Law, and these concepts have formed the basis of subsequent design decisions. Design iterations have both solved existing problems and exposed new challenges. The current device design is greatly improved over early attempts due to the incorporation of technologies that have recently become available as the result of progress in the fields of materials and electronics and due to the lessons learned over many years of research under the guidance of Dr. Kolff. This article describes, from its inception, the last major research project of Dr. Kolff prior to his retirement. The discussion centers around development, problems and their solutions, and the reasoning for given solutions.
The Effects of Various Extracellular Matrices on Renal Cell Attachment to Polymer Surfaces During the Development of Bioartificial Renal Tubules
Authors: Kanai Nobuyuki , Fujita Yuji , Kakuta Takatoshi , Saito Akira
Published: March 2003

Extracellular matrices (ECM) are utilized for obtaining better cell attachment to polymer surfaces in cell cultures. To establish beneficial bioartificial renal tubules, tubular epithelial cells and ECM were investigated in this study. MDCK cells and KU‐2 cells were seeded onto 96 well plates which had been precoated with collagen types I and IV, laminin, and fibronectin. The culture media were removed and replaced with new ones at 15, 30, 60, 90, 120, and 150 min and 24 h after start time to evaluate the incubation time effects. The degrees of cell attachment onto ECM were measured by MTT assay. In the MDCK cell culture, better cell attachment was observed between 60 min and 24 h after incubation start time with the use of laminin at a concentration of 5 μg/ml, 60 min and more after incubation start time with the use of fibronectin at the concentrations of 1 and 4 μg/ml, or 30 min and more after incubation start time with the use of fibronectin at the concentrations of 16 and 32 μg/ml. On the other hand, in the KU‐2 cell culture, better cell attachment was observed between 15 and 60 min after the incubation start time or 24 h after the incubation start time with the use of laminin at a concentration of 40 μg/ml. These data suggest that various cells possibly each have a most suitable ECM kind, best concentration, and best incubation time.
Pathophysiological Role of Leptin in Patients with Chronic Renal Failure, in Kidney Transplant Patients, in Patients with Essential Hypertension, and in Pregnant Women with Preeclampsia
Authors: Kokot Franciszek , Więcek Andrzej , Adamczak Marcin , Ulman Izabela , Spiechowicz Urszula , Cieplok Joanna , Mesjasz Jacek
Published: March 2003

This paper is a summary of results obtained in our studies on leptinemia in patients with chronic renal failure treated with recombinant human erythropoietin (rHuEPO), in kidney transplant patients, in patients with essential hypertension, and in pregnant women with preeclampsia. In this study, we found that rHuEPO treatment has a suppressive effect on leptinemia in patients with end‐stage renal failure. These results suggest that the appetite stimulating effect of rHuEPO may be mediated by a reduction of leptin synthesis and release. At the early stage of successful kidney transplantation, a significant decline of leptinemia was noticed, which was not related either to the excretory function of the graft or the kind and dose of immunosuppressants. In kidney transplant patients with grafts functioning well for 2.5 years, significantly elevated leptinemia was found. From these results, we may conclude that factors other than the excretory function of the graft and the kind and dosage of immunosuppressants may be involved in the pathogenesis of abnormal leptinemia in these patients. Both in normotensive subjects and patients with essential hypertension, a positive correlation was found between leptinemia and mean blood pressure, suggesting that leptin may be involved in the regulation of blood pressure. Both healthy and preeclamptic pregnant women show higher leptinemia than nonpregnant women. In preeclamptic women, leptin levels in maternal vein blood, umbilical cord blood, and amniotic fluid were significantly higher than respective values found in healthy pregnant women. In contrast to healthy pregnant and nonpregnant women, in women with preeclampsia, no correlation was found between the body mass index (BMI) and leptinemia. In preeclamptic women the abnormally elevated leptinemia was not related to blood pressure. Finally, no correlation was found between leptinemia in maternal and umbilical cord blood. From these studies, it follows that the elucidation of abnormal leptin secretion in the pathogenesis of preeclampsia needs further study.
Investigation of Plasma Protein Adsorption on Functionalized Nanoparticles for Application in Apheresis
Authors: Mullaney Mark , Groth Thomas , Darkow Rita , Hesse Ruth , Albrecht Wolfgang , Paul Dieter , Von Sengbusch Günter
Published: March 2003

Particles with specific ligands for the adsorption of plasma proteins can be used in therapeutic or preparative apheresis. The development of these particles may benefit from an improved knowledge of the relationship between protein adsorption and the structure of ligands. Nanoparticles were functionalized with aliphatic diamines of increasing chain length; with the amino acids lysine, tryptophan, histidine, and their corresponding amines; and with tryptophan and histidine spaced with diamines of different length. Suitable protocols were developed for the washing of particles and the subsequent desorption of proteins adsorbed from human plasma. The adsorption pattern, as well as the quantification of the overall adsorption of proteins on these modified particles, was investigated with gel electrophoresis. This was followed by immuno‐blotting which yielded specific assessments of bound human serum albumin and fibrinogen. The comparison of protein adsorption with surface charge density and measured hydrophobicities yielded no simple correlations although in general more hydrophobic ligands bound higher quantities of protein. The detection of human serum albumin yielded similar results because it was observed for overall protein adsorption while the adsorption of fibrinogen expressed a different pattern. In this case, particular nanoparticles functionalized with aliphatic diamines bound significantly higher amounts of fibrinogen than all other ligands.
Usefulness of Postoperative Percutaneous Cardiopulmonary Support Using a Centrifugal Pump: Retrospective Analysis of Complications
Authors: Yamashita Chojiro , Ataka Keiji , Azami Takashi , Nakagiri Keitarou , Wakiyama Hidetaka , Okada Masayoshi
Published: March 2003

Between January 1992 and December 1997, we employed percutaneous cardiopulmonary support (PCPS) using a centrifugal pump in 25 patients. In 21 of them, PCPS was used postcardiotomy. These patients could not be weaned from cardiopulmonary bypass due to profound ventricular failure. As for the other 4 patients, PCPS was used preoperatively for profound cardiogenic shock, a thrombosed valve, a stuck valve, and pulmonary embolization. Nine patients (43%) were weaned from PCPS (Group 1), and 3 (14%) were discharged from the hospital. The other 12 patients (57%) had perioperative extensive myocardial infarction and could not be weaned (Group 2). The causes of death were bleeding and multiple organ failure (MOF) associated with ventricular failure. The reasons for MOF were perioperative massive transfusion and hepatic congestion caused by sustained ventricular failure. To increase the survival rate, complete hemostasis and prevention of increased central venous pressure by early use of PCPS are necessary.
A Future Prediction Type Artificial Heart System
Authors: Yambe Tomoyuki , Tanizuka Noboru , Tanaka Akira , Yoshizawa Makoto , Abe Ken‐ichi , Takeda Hiroshi , Tabayashi Kou‐ichi , Nitta Shin‐ichi
Published: March 2003

The demand of the biological system needs to be predicted to consider the quality of life (QOL) of a patient with an artificial heart system. The purpose of this study was the prediction of the imminent cardiac output and the predictive control for an artificial heart. For that purpose, autonomic nerve information was applied in this study. Nervous sympathicus action potentials were measured, and a prediction function of cardiac output was made using the sympathetic tone and preload and afterload measurement with multiple regression analysis. The predicted value showed significant correlation with the measured value after 2.9 s. Currently, however, long‐term instrumentation of the nervous sympathicus potential is difficult. Thus, hemodynamic fluctuations, which recently have attracted attention, were used in this study. A prediction function using the Mayer wave, which represented nervous sympathicus, was determined. As a result, mid‐term prediction became possible. Furthermore, a measurement of the vagal nerve was used as a possible long‐term prediction parameter. For long‐term prediction, Hurst exponent analysis was used in this study. Vagal nerve discharges in the changing position showed alteration of long‐term determination. In conclusion, the future prediction control of an artificial heart takes shape using these prediction functions.
Bioartificial Liver Support System Using Porcine Hepatocytes Entrapped in a Three‐Dimensional Hollow Fiber Module with Collagen Gel: An Evaluation in the Swine Acute Liver Failure Model
Authors: Naka Shigeyuki , Takeshita Kazuyoshi , Yamamoto Takumi , Tani Tohru , Kodama Masashi
Published: March 2003

Abstract: The perfusion culture system of hepatocytes entrapped in a three‐dimensional hollow fiber module with collagen gel is expected to realize an effective bioartificial liver (BAL) support system. The BAL module contained 5.4 billion porcine hepatocytes, which is approximately 7% of the total liver, supplied adequate metabolic functions, and improved the survival of the experimental acute liver failure swine. Improvement of the prothrombin time by the BAL treatment was not significant; however, the bleeding tendency was suppressed, which resulted in a significantly prolonged survival time of the animals in the BAL treatment group. A drastic up‐regulation of the expression of the mRNA for plasminogen activator inhibitor 1 (PAI‐1), which is known as an inhibitor for fibrinolysis, may explain the suppression of the bleeding tendency. These results support the efficacy of our BAL system for the treatment of acute liver failure.
Cardiac Autonomic Nervous Function During Long‐Term Nonpulsatile Left Heart Bypass
Authors: Nishinaka Tomohiro , Tatsumi Eisuke , Nishimura Takashi , Taenaka Yoshiyuki , Masuzawa Toru , Nakata Masako , Takano Hisateru , Koyanagi Hitoshi
Published: March 2003

We investigated the changes in cardiac autonomic nervous activities during long‐term nonpulsatile left heart bypass (NLHB) by analyzing heart rate variability. A pulsatile ventricular assist device was installed in 3 goats, and pulsatile left heart bypass (PLHB) was conducted for 2 weeks. Then, NLHB was maintained for the following 4 weeks. The segmental data of the R‐R intervals (R‐Rs) was analyzed by maximum entropy spectral analysis. Changes in evaluated parameters from the last week of PLHB to the 4th week of NLHB were as follows: the mean R‐Rs increased from 511 ms to 692 ms; the coefficient of variation of R‐R increased from 10.2 to 14.1%; the power of the low frequency band (LF) increased from 747 ms2 to 2,855 ms2; the power of the high frequency band (HF) increased from 512 ms2 to 1,270 ms2; and the ratio of LF to HF increased from 2.6 to 6.5. These results indicated that the cardiac autonomic nervous activity, both sympathetic and parasympathetic, increased during long‐term NLHB.
Flow Visualization Study to Improve Hemocompatibility of a Centrifugal Blood Pump
Authors: Nishida Masahiro , Asztalos Balázs , Yamane Takashi , Masuzawa Toru , Tsukiya Tomonori , Endo Seiko , Taenaka Yoshiyuki , Miyazoe Yuki , Ito Kazuyuki , Konishi Yoshiaki
Published: March 2003

A correlation study was conducted among quantitative flow visualization analysis, computational fluid dynamic analysis, and hemolysis tests regarding the flow in a centrifugal blood pump to prevent hemolysis. Particular attention was paid to the effect of the impeller/casing gap widths on the flow in the volute and in the outlet. Flow vector maps were obtained for 250% scaled‐up models with various geometries, using an argon ion laser light sheet, a high speed video camera, and particle tracking velocimetry. In terms of the results, in the small radial gap model, high shear occurred near the inside wall of the outlet and stagnation near the outside wall of the outlet whereas the standard model maintained smooth flow and low shear. The small radial gap model showed a lower head and greater hemolysis than the standard model. This head decrease could be partly restored by relocating the outlet position; however, the hemolysis level hardly decreased. From these results, it was found that the small radial gap itself is important. It was also confirmed by detailed flow visualization and simple laminar shear analysis near the wall that the small radial gap caused a wider high shear layer (110–120 μ m) than the standard model (~80 μm). In the small radial gap model, the high shear layer in the outlet (~50 μm) is much narrower than that in the volute. Flow visualization together with the aid of computational fluid dynamic analysis would be useful to eliminate the causes of hemolysis.
Total Vascular Resistance and Blood Flow Frequency During Left Ventricular Assistance Using a Vibrating Flow Pump
Authors: Kobayashi  , Owada  , Yambe  , Nitta  , Fukuju  , Hongoh  , Hashimoto
Published: March 2003

A vibrating flow pump (VFP) can generate high frequency oscillated blood flow within 10~30 Hz by the oscillation of its central tube. A totally implantable artificial heart using a VFP is being developed as a unique type of blood pump. In this study, left ventricular (LV) assist circulation was performed using a VFP. The total vascular resistance and driving frequency of the VFP were estimated from their relationship. The effect of oscillation on the vascular system was studied by the frequency analysis method and vascular impedance. Adult goats were anesthetized by halothane using an inhaler and a left fourth thoracotomy was performed. The inflow cannula was inserted into the left ventricle, and the outflow cannula was sutured to the descending aorta. The VFP and a centrifugal pump were set in parallel for alternation and comparison. The driving frequency of the VFP was changed and included 15, 20, 25, and 30 Hz. The hemodynamic parameters were continuously recorded during experiments by a digital audio tape (DAT) data recorder. The internal pressure of the left ventricular cavity and aortic pressure were monitored by the pressure manometers continuously. One hundred percent LV assistance was judged by the separation of LV and aortic pressure. The total vascular resistance was decreased by the start of operation of each pump. The decrease during flow using the VFP was not as large as that using a centrifugal pump (CP). The arterial input impedance during oscillated blood flow by the VFP showed a slow curve appearance. It was similar to the frequency characteristics curve of natural heart beats within the lower frequencies. The study of arterial impedance may be important for the estimation of the reflection of the pulsatile wave from the arterial branch, among other things.
Early Detection of Neurologic Injury and Issues of Rehabilitation after Pediatric Cardiac Extracorporeal Membrane Oxygenation
Authors: Golej Johann , Trittenwein Gerhard
Published: March 2003

Abstract: Neurological impairment results in a significant population of children after extracorporeal membrane oxygenation (ECMO) for treatment of otherwise intractable circulatory failure. Pre‐ECMO hypoxia/ischemia, reperfusion injury, and impaired cerebral perfusion during low output situations possibly aggravated by harmful effects of apulsatile perfusion are discussed in terms of possible etiological reasons. To develop preventive strategies or to enable curative measure, early detection of neuronal injury seems mandatory. Electroencephalographic surveillance and/or monitoring of evoked potentials and monitoring of cerebral oxygenation by means of near infrared spectroscopy or jugular venous bulb oxygen saturation, as well as measurements of serum neuron specific enolase, S‐100 protein, and brain type creatine kinase can be employed clinically. To improve functional outcome following neuronal injury, early rehabilitation seems essential to minimize the resulting effects on physical, cognitive, and emotional development.
Tissue Engineered Artificial Skin Composed of Dermis and Epidermis
Authors: Yang Eun Kyung , Seo Young Kwon , Youn Hee Hun , Lee Doo Hoon , Park Sue Nie , Park Jung Keug
Published: March 2003

Abstract: We made an artificial skin comprised of a stratified layer of keratinocytes and a dermal matrix with a type I collagen containing fibroblasts. In this work, we showed keratinocyte behavior under primary culture, gel contractions varying with concentration of collagen solution, and cell growth plots in the collagen gel. The optimum behavior of dermal equivalent could be obtained using 3.0 mg/ml collagen solution and attached gel culture. The attached gel culture had a jumping effect of growth factor on cell growth at the lag phase. To develop the artificial skin, 1× 105 cells/cm2 of keratinocytes were cultured on the dermal equivalent at air‐liquid interface. Finally, to overcome the problem that artificial skin of collagen gel was torn easily during suturing of grafting, we prepared histocompatible collagen mesh and attached the mesh to the bottom of the gel. Cultured artificial skins were successfully grafted onto rats.
Analysis of Hemodynamic Response with 1/R Control on Biventricular Bypass Goat
Authors: Abe Yusuke , Chinzei Tsuneo , Isoyama Takashi , Mochizuki Shuichi , Saito Itsuro , Karita Tatsuro , Ono Toshiya , Kouno Akimasa , Baba Kazunori , Imachi Kou
Published: March 2003

Abstract:A conductance and arterial pressure based method (1/R control) to determine the cardiac output (CO) of a total artificial heart (TAH) was developed to provide a central nervous system with control over the output of TAH. In order to clarify the deference in hemodynamic response between natural heart and 1/R control, biventricular bypass was introduced in the goat. After 2 pneumatically driven sac‐type blood pumps were connected to the natural heart, the pulmonary artery was totally clamped to acquire 100% right heart bypass, and the ascending aorta was stenosed to acquire about 60 to 90% left heart bypass; 1/R control was performed substituting the output of the right artificial heart for the CO. The results demonstrated that stable control could be achieved. A discrepancy was often seen between the pulse rate (PR) of the artificial heart and the heart rate (HR) in absolute value. However, the relative changes of PR were quite similar to that of HR for the most part, indicating that the responses of 1/R control were the duplication of natural cardiac responses in normal daily activity.
The Effect of Sudden Failure of a Rotary Blood Pump on Left Ventricular Performance in Normal and Failing Hearts
Authors: Nishida Takahiro , Meyns Bart , Zietkiewicz Miroslaw , Perek Bartolomeij , Xia Zhengyuan , Goebel Christoph , Reul Helmut , Flameng Willem
Published: March 2003

Abstract: We investigated the hemodynamic effect of regurgitation (or back‐flow) due to sudden failure of a rotary blood pump (diagonal pump). Seven healthy sheep (Group C) and 7 with chronic heart failure (Group F) were studied. Chronic heart failure was obtained by intracoronary injection of microspheres several weeks earlier. Left ventricular function and ventricular efficacy were assessed by the pressure–volume relationship. The back‐flow through the stopped pump was significantly lower in Group F (2.3 ± 0.34 L/min) than in Group C (2.8 ± 0.33 L/min). Mean aortic blood pressure dropped significantly from 68.3 ± 9.65 to 61.9 ± 9.75 mm Hg in Group C and from 62.5 ± 9.12 to 51.5 ± 9.08 in Group F but remained stable during the 15 min period of pump stop. Parameters of left ventricular contractility (preload recruitable stroke work) dropped significantly in both groups, remained stable during the pump stop, and returned to baseline values 30 min after the end of back‐flow. The ventricular efficacy (in terms of energy transfer) was tolerant against this acute volume overload even in the failing hearts. Sudden pump failure of a rotary blood pump leads to an acute depression of the hemodynamic state and myocardial contractility. However, this depression remained stable over 15 min, did not lead to further deterioration of the animals, and was completely reversible.
Magnetically Suspended Rotary Blood Pump with Radial Type Combined Motor‐Bearing
Authors: Masuzawa Toru , Kita Toshiyuki , Matsuda Ken‐ichi , Okada Yohji
Published: March 2003

Abstract: A magnetically suspended centrifugal blood pump is being developed with a combined motor‐bearing for long‐term ventricular assist systems. The combined motor‐bearing actively suspends a rotor in a radial direction to deal with radial force unbalance in the pump and rotates the rotor by using the electric magnetic field. Therefore, the pump has no mechanical parts such as bearings of the motor and has a long lifetime. The developed pump consists of a thin rotor with a semi open‐type 6 vane impeller and a stator to suspend and rotate the rotor. The rotor has 4‐pole permanent magnets on the circumferential surface. The outer diameter and the thickness of the rotor are 60 mm and 8 mm, respectively. Axial movement and tilt of the rotor are restricted by passive stability based on the thin rotor structure. Radial movements of the rotor, such as levitation in radial direction and rotation, are controlled actively by using electric magnets of the stator. The electric magnet coils to produce levitation and rotation forces are constructed on the periphery stator. The p ± 2‐pole algorithm and the synchronous motor mechanism are adopted to levitate and rotate the rotor. The radial gap between the rotor and the stator is 1 mm. A closed‐loop circuit filled with water was connected to the developed pump to examine the basic performance of the pump and the magnetic suspension system. Maximum rotational speed, flow rate, and head were 2,800 rpm, 11 L/min, and 270 mm Hg, respectively. The rotor with the impeller could be suspended completely during the entire pumping process. We conclude the pump with the combined motor‐bearing has sufficient performance for the blood pump.