bluuebunny/crossref_metadata_2025 huggingface dataset:
Neutrophil role in pulmonary paracoccidioidomycosis depends on the resistance pattern of hosts
Authors: Pina Adriana , Saldiva Paulo Hilário Nascimento , Restrepo Luz Elena Cano , Calich Vera L G
Published: April 2006

The immunoprotective and immunomodulatory role of neutrophils during pulmonary infection of resistant (A/J) and susceptible (B10.A) mice to Paracoccidioides brasiliensis was investigated. First, comparative studies about early cellular influx to the lungs demonstrated higher numbers of neutrophils in susceptible rather than in resistant mice. Neutrophil depletion resulted in decreased survival times of susceptible but not resistant mice. In both mouse strains, depletion led to increased fungal burdens at Week 1 of infection; however, only susceptible mice remained with increased pulmonary fungal loads and presented a dramatic fungal dissemination to liver and spleen. At Week 1 of infection, treated and untreated B10.A and A/J mice were negative for delayed-type hypersensitivity (DTH) reactions, which remained negative for the susceptible strain. In contrast, from the second week onward, control and neutrophil-depleted, resistant mice became positive for DTH reactions. In B10.A mice, neutrophil depletion resulted in increased levels of interleukin (IL)-12 and IL-4 in the lungs, high levels of hepatic cytokines, and increased synthesis of T helper cell type 1 (Th1)- and Th2-regulated antibodies [immunoglobulin G1 (IgG1), IgA, and IgG3]. In neutrophil-depleted A/J mice, high levels of pulmonary IL-12 and granulocyte macrophage-colony stimulating factor were concomitant to diminished levels of hepatic cytokines and increased amounts of Th1-regulated isotypes (IgG2a, IgG2b, and IgG3). Differently from primary infection, neutrophil depletion did not alter immunoprotection in secondary paracoccidioidomycosis. As a whole, our data showed that the genetic patterns of hosts exert an important influence on the immunoprotective and immunoregulatory functions of neutrophils, which appear to be essential in situations devoid of cell-mediated immunity.
Macrophage nutriprive antimicrobial mechanisms
Authors: Appelberg Rui
Published: April 2006

In addition to oxidative and antibiotic mechanisms of antimicrobial activity, macrophages are able to deprive intracellular pathogens of required nutrients. Thus, microbial killing may not rely only in the toxic environment the microbe reaches but also may result from the scarcity of nutrients in the cellular compartment it occupies. Here, we analyze evidence for such nutriprive (from the latin privare, to deprive of nutrients), antimicrobial mechanisms. Although the direct analysis of nutrient availability is most often not feasible, indirect evidence of lack of nutrients in the microbial organelles has been inferred from the study of mutants, the analysis of gene expression, and the consequences of changing the intracellular location of the pathogen. We propose that according to the microbe and its survival strategy, different mechanisms to impede access to nutrients may be constitutively present or may be induced by cytokines and other pathways. Thus, membrane transporters may remove nutrients from vacuolar compartments, and enzymes may degrade some growth factors. A series of diverse compounds may sequester other molecules required for microbial growth, as exemplified by the action of iron chelators. Modulation of vesicular trafficking may prevent the fusion of certain vesicles containing nutrients with those containing the pathogen, counteracting the evasion strategies of the pathogen. The understanding of these mechanisms will certainly help in designing new therapeutic and prophylactic approaches to preventing infectious diseases.
Bovine polymorphonuclear cells passively acquire membrane lipids and integral membrane proteins from apoptotic and necrotic cells
Authors: Whale Tyler A , Beskorwayne Terry K , Babiuk Lorne A , Griebel Philip J
Published: April 2006

Immune cells can acquire membrane fragments and integral membrane proteins from dead and dying cells or in the case of immature dendritic cells, from live cells. While investigating the possibility that bovine polymorphonuclear cells (PMNs) might present antigen, coculture assays confirmed that integral membrane proteins were transferred rapidly and efficiently to bovine PMNs from a variety of apoptotic and necrotic cells. Specifically, we observed that PMNs rapidly acquired proteins such as major histocompatibility complex (MHC) class II and CD3 from a variety of syngeneic, allogeneic, and xenogeneic cell types. Such acquisition occurred within 40 min of PMN coculture with isolated peripheral blood mononuclear cells, and this acquisition occurred with equal efficiency at 4°C and 37°C. The transfer of murine MHC class II to bovine PMNs precluded the possibility of endogenous protein expression. We also demonstrated the transfer of fluorescently labeled plasma membrane lipids and biotinylated integral membrane proteins. Collectively, these observations support the hypothesis that membrane protein transfer was mediated by the fusion of membrane fragments or microvesicles with the PMN plasma membrane and not by phagocytosis of cell fragments. These observations indicate that phenotypic studies of PMNs must consider circumstances whereby PMNs may passively acquire membrane lipids and a variety of integral membrane proteins from dead or dying cells.
Anti-CCR7 monoclonal antibodies as a novel tool for the treatment of chronic lymphocyte leukemia
Authors: Alfonso-Pérez Manuel , López-Giral Sonia , Quintana Nuria E , Loscertales Javier , Martín-Jiménez Patricia , Muñoz Cecilia
Published: April 2006

To date, chronic lymphocytic leukemia (CLL) remains incurable with current treatments, which include the monoclonal antibodies (mAbs) rituximab and alemtuzumab. The efficacy of rituximab is modest when used as single agent, and alemtuzumab induces severe immunosuppression. To develop more potent and specific therapies, we propose the CC chemokine receptor 7 (CCR7) as an attractive target molecule to treat CLL, as it not only fulfills the requirements of a high-surface expression and a good level of tissue specificity, but it also plays a crucial role in mediating the migration of the tumor cells to lymph nodes (LNs) and thus, in the development of clinical lymphadenopathy. In the current work, murine anti-human CCR7 mAb mediated a potent, complement-dependent cytotoxicity (CDC) against CLL cells while sparing normal T lymphocytes from the same patients. The sensitivity to CDC was related to the antigenic density of CCR7. Moreover, these mAb blocked the in vitro migration of CLL cells in response to CC chemokine ligand 19 (CC219), one of the physiological ligands of CCR7. Conversely, CLL cells were poorly lysed through antibody-dependent, cell-mediated cytotoxicity (ADCC), probably as a result of the murine origin and the isotype of the anti-CCR7 mAb used. Molecular engineering techniques will allow us to obtain chimeric or humanized anti-CCR7 mAb to reach the best clinical response for this common and yet incurable leukemia.
Developments in the Measurement of Subjective Well-Being
Authors: Kahneman Daniel , Krueger Alan B
Published: April 2006

Direct reports of subjective well-being may have a useful role in the measurement of consumer preferences and social welfare, if they can be done in a credible way. Can well-being be measured by a subjective survey, even approximately? In this paper, we discuss research on how individuals' responses to subjective well-being questions vary with their circumstances and other factors. We will argue that it is fruitful to distinguish among different conceptions of utility rather than presume to measure a single, unifying concept that motivates all human choices and registers all relevant feelings and experiences. While various measures of well-being are useful for some purposes, it is important to recognize that subjective well-being measures features of individuals' perceptions of their experiences, not their utility as economists typically conceive of it. Those perceptions are a more accurate gauge of actual feelings if they are reported closer to the time of, and in direct reference to, the actual experience. We conclude by proposing the U-index, a misery index of sorts, which measures the proportion of time that people spend in an unpleasant state, and has the virtue of not requiring a cardinal conception of individuals' feelings.
Electronic Trading in Stock Markets
Authors: Stoll Hans R
Published: April 2006

Modern trading technology clashes with the traditional organization of a stock exchange, where transactions were consummated via face-to-face negotiation. The modern trading facility is no longer a place. Rather, it is a computer system over which transactions are entered, routed, executed and cleared electronically with little or no human intervention. In this article, I examine how electronic trading has altered stock markets. I begin with an overview of how the stock trading process works and then address a number of questions. How have the jobs of traditional stock market dealers on the NYSE and on Nasdaq been affected by electronic trading? How do electronic communications networks differ from traditional markets? How has electronic trading affected bid-ask spreads and commission costs? What subtle issues arise in electronic trading when dealer and customer interests diverge? Will computer programs replace human judgment? What is the effect of electronic trading on the number and types of securities markets? What is the role of regulation in electronic markets?
What's in a Surname? The Effects of Surname Initials on Academic Success
Authors: Einav Liran , Yariv Leeat
Published: April 2006

In this paper, we focus on the effects of surname initials on professional outcomes in the academic labor market for economists. We begin our analysis with data on faculty in all top 35 U.S. economics departments. Faculty with earlier surname initials are significantly more likely to receive tenure at top ten economics departments, are significantly more likely to become fellows of the Econometric Society, and, to a lesser extent, are more likely to receive the Clark Medal and the Nobel Prize. These statistically significant differences remain the same even after we control for country of origin, ethnicity, religion or departmental fixed effects. As a test, we replicate our analysis for faculty in the top 35 U.S. psychology departments, for which coauthorships are not normatively ordered alphabetically. We find no relationship between alphabetical placement and tenure status in psychology. We suspect the “alphabetical discrimination” reported in this paper is linked to the norm in the economics profession prescribing alphabetical ordering of credits on coauthored publications. We also investigate the extent to which the effects of alphabetical placement are internalized by potential authors in their choices to work with different numbers of coauthors as well as in their willingness to follow the alphabetical ordering norm.
Some Uses of Happiness Data in Economics
Authors: Tella Rafael Di , MacCulloch Robert
Published: April 2006

Happiness research is based on the idea that it is fruitful to study empirical measures of individual welfare. The most common is the answer to a simple well-being question such as “Are you Happy?” Hundreds of thousands of individuals have been asked this question, in many countries and over many years. Researchers have begun to use these data to tackle a variety of important questions in economics. Some require strong assumptions concerning interpersonal comparisons of utility, but others make only mild assumptions in this regard. They range from microeconomic questions, such as the way income and utility are connected, to macroeconomic questions such as the tradeoff between inflation and unemployment, including large areas in political economy. Public policy is another area where progress using happiness data is taking place. Given the central role of utility notions in economic theory, we argue that the use of happiness data in empirical research should be given serious consideration.
Markets: Beer in Germany and the United States
Authors: Adams William James
Published: April 2006

Between 1950 and 2000, the four-firm producer-concentration ratio for beer increased from 22 to 95 in the United States; and Anheuser-Busch's share of domestic output ballooned from 6 to 54 percent. In Germany, concentration has risen, but it remains low. In 2000, the four-firm producer-concentration ratio was just 29; and the eight-firm ratio in Germany was smaller than the one-firm ratio in the United States. In 2005, after five years of important mergers involving big brewers, the German beer industry was still much less concentrated than its American counterpart. In this article, I discuss several candidate explanations for the failure of beer-producer-concentration to rise as much in Germany as in the United States: the relevance of the new technologies to German brewers, the preferences of German consumers, the rules for advertising on German television and other factors, largely absent from the consensus interpretation of American experience. I find that market structure depends on a remarkably broad range of factors, extending well beyond technological opportunity and market size.
RDE-4 preferentially binds long dsRNA and its dimerization is necessary for cleavage of dsRNA to siRNA
Authors: Parker Greg S. , Eckert Debra M. , Bass Brenda L.
Published: April 2006

In organisms ranging from Arabidopsis to humans, Dicer requires dsRNA-binding proteins (dsRBPs) to carry out its roles in RNA interference (RNAi) and micro-RNA (miRNA) processing. In Caenorhabditis elegans, the dsRBP RDE-4 acts with Dicer during the initiation of RNAi, when long dsRNA is cleaved to small interfering RNAs (siRNAs). RDE-4 is not required in subsequent steps, and how RDE-4 distinguishes between long dsRNA and short siRNA is unclear. We report the first detailed analysis of RDE-4 binding, using purified recombinant RDE-4 and various truncated proteins. We find that, similar to other dsRBPs, RDE-4 is not sequence-specific. However, consistent with its in vivo roles, RDE-4 binds with higher affinity to long dsRNA. We also observe that RDE-4 is a homodimer in solution, and that the C-terminal domain of the protein is required for dimerization. Using extracts from wild-type and rde-4 mutant C. elegans, we show that the C-terminal dimerization domain is required for the production of siRNA. Our findings suggest a model for RDE-4 function during the initiation of RNAi.
Identification of RNA-binding proteins that regulate FGFR2 splicing through the use of sensitive and specific dual color fluorescence minigene assays
Authors: Newman Emily A. , Muh Stephanie J. , Hovhannisyan Ruben H. , Warzecha Claude C. , Jones Richard B. , Mckeehan Wallace L. , Carstens Russ P.
Published: April 2006

We have developed a series of fluorescent splicing reporter minigenes for the establishment of cell-based screens to identify splicing regulatory proteins. A key technical advance in the application of these reporters was the use of two different fluorescent proteins: EGFP and monomeric Red Fluorescent Protein (mRFP). Through establishment of stable cell lines expressing such dual color fluorescent reporters, these minigenes can be used to perform enhanced screens for splicing regulatory proteins. As an example of such applications we generated fluorescent minigenes that can be used to determine the splicing of mutually exclusive FGFR2 exons IIIb and IIIc by flow cytometry. One minigene contained a coding sequence for EGFP whose translation was dependent on splicing of exon IIIb, whereas a second minigene required exon IIIc splicing for translation of an mRFP coding sequence. Stable incorporation of both minigenes into cells that express endogenous FGFR2-IIIb or FGFR2-IIIc resulted in EGFP or mRFP fluorescence, respectively. Cells stably transfected with both minigenes were used to screen a panel of cDNAs encoding known splicing regulatory proteins, and several were identified that induced a switch in splicing that could be detected specifically by an increase in green, but not red, fluorescence. We further demonstrated additional minigenes that can be used in dual color fluorescent screens for identification of splicing regulatory proteins that function through specific intronic splicing enhancer elements (ISEs). The methods and minigene designs described here should be adaptable for broader applications in identification of factors and mechanisms involved in alternative splicing of numerous other gene transcripts.
Alloys, Shape Memory
Authors: Kim Young Kon
Published: April 2006

A shape memory alloy is a metallic substance that has a memory for shape combined with superelasticity. The mechanisms of a nickel‐titanium alloy’s shape memory effect and superelasticity are described based on thermally induced or stress induced martensite phase transformations. The thermomechanical characteristics, corrosion properties, and biocompatibility of Ni‐Ti shape memory alloys are reviewed for the design of shape memory devices. Manufacturing methods, including refining, processing, shape memory programming, and transformation temperature range measuring methods are summarized for practical applications. Finally, some applications in medical devices are reviewed as examples of current trends in the use of shape memory alloys.
Ambulatory Monitoring
Authors: Wang Haibo , Elsharydah Ahmad , Cork Randall , Frazier James
Published: April 2006

Advances in technology, especially computer sciences, have made ambulatory monitoring with medical instruments an increasingly important tool in the diagnosis of some diseases and medical conditions. Current devices in use, such as for Holter monitoring and ambulatory blood pressure and blood glucose monitoring, are described.
Analytical Methods, Automated
Authors: Ramanathan Lakshmi , Sarkozi Laszlo
Published: April 2006

Automated analyzers were developed to improve the processes and methodologies of analyzing specimens and samples. Specific progress in specimen handling and collection, automated analyzers, chemistry analyzers, and clinical laboratory automation along with some financial implications will be discussed.
Anesthesia, Computers in
Authors: Wang Le Yi , Wang Hong
Published: April 2006

Computer technology has played an essential role in improving anesthesia patient care and reducing healthcare costs. This article provides a synopsis of computer applications in the areas of anesthesia monitoring, anesthesia information systems, computer simulations of human patients, computer anesthesia control, computer‐assisted diagnosis and decisions, and telemedicine in anesthesia.
Anesthesia Machines
Authors: Loeb Robert , Feldman Jeffrey
Published: April 2006

Anesthesia machines are medical devices that are used to safely and precisely administer inhalational anesthesia to patients undergoing surgical procedures. They provide a means for anesthesia providers to: 1) Deliver a precise mixture of inhaled gases to the patient; 2) Support multiple modes of ventilation (i.e., spontaneous, manually assisted, and mechanically controlled); 3) Conserve the use of anesthetic vapors and gases; 4) Minimize contamination of the operating room atmosphere by anesthetic vapors and gases; and 5) Minimize patient injury in the event of use error or equipment malfunction. Modern anesthesia delivery systems incorporate the following functional components: gas mixing device, breathing circuit, ventilator, waste gas scavenger system, and patient and system monitors. This article provides an overview of the design and safety features of modern anesthesia machines, and emphasizes the ongoing transition from mechanical to electronic technologies.
Anger Camera
Authors: Madsen Mark T.
Published: April 2006

The Anger camera (also known as the gamma camera or scintillation camera) was invented by Hal O. Anger in 1957 and it is still the primary imaging instrument used in nuclear medicine. Although there have been many improvements in this device resulting from better components, advanced electronics, and digital implementations, the fundamental operation of the Anger camera has not changed. The Anger camera uses one large, thin sodium iodide crystal for absorbing gamma‐ray energy and converting that energy into visible light. The light signals are sampled by an array of photomultilier tubes that determine
X
and
Y
locations and the energy of detected events. When a signal from a detected event falls within a preselected energy range, the
X
and
Y
locations are recorded in either list or histogram modes. The Anger camera uses multiholed lead collimators as the image‐forming aperture. Anger cameras are used for a wide range of radionuclide imaging including single‐photon emission computed tomography (SPECT) and positron emission tomography (PET) as well as conventional nuclear medicine studies.
Anorectal Manometry
Authors: Tuteja Ashok K. , Wahlen George E. , Rao Satish S.C.
Published: April 2006

Evaluation of anorectal function can provide indications for the pathophysiology of disorders that affect defecation, continence, or anorectal pain. Anorectal manometry quantifies anal sphincter tone and assesses anorectal sensory response, recto anal reflexes, and rectal compliance.
Arrhythmia Analysis, Automated
Authors: Schuckers Stephanie A. C.
Published: April 2006

Arrhythmias are an abnormal electrical activation of the heart, which in some cases can be immediately life threatening. Automated arrhythmia analysis is the detection of arrhythmias through the use of a computer. Examples of medical devices that use automated arrhythmia detection include implantable defibrillators, public access automated external defibrillators, atrial defibrillators, and more. These devices provide treatment for arrhythmias without human oversight. The primary focus of this article is automated arrhythmia detection algorithms developed for the implantable cardioverter defibrillator (ICD). An implantable cardioverter defibrillator is a device that provides an electrical shock to ventricular fibrillation and tachycardia to terminate it and restart normal sinus rhythm (NSR). Other medical devices that use automated arrhythmia analysis will also be described briefly.
Bioelectrodes
Authors: McAdams Eric
Published: April 2006

Good electrode design is not as simple and straightforward a matter as is often assumed, and all electrode designs are not equal in performance for a given application. One must therefore not simply choose an electrode with as conductive a metal plate as possible. Different materials and designs are required for different applications, and it is often best to start with the design of the electrode when developing a new monitoring or stimulation system, rather than leaving it to the end of the project.

Key aspects of biomedical electrode design and performance are reviewed. Historical developments are briefly presented, as many of the early designs are still being used, albeit sometimes in different areas of monitoring or therapy. Ideas for electrode design can also be gleaned from the present state‐of‐the‐art other branches of monitoring or electrotherapy.
Bioheat Transfer
Authors: Valvano Jonathan W.
Published: April 2006

This article presents the characteristics of bioheat transfer that distinguish it from nonliving systems, including the effects of blood perfusion on temperature distribution, coupling with biochemical processes, therapeutic and injury processes, and thermoregulation.
Ionizing Radiation, Biological Effects of
Authors: Goldberg Zelenna
Published: April 2006

Radiation biology refers to all biologic responses induced in cells and tissues by ionizing radiation (IR), a term that encompasses the study of all action of ionizing radiation on living things. IR causes the ejection of an orbital electron when the radiation interacts with tissue. IR interacts with all parts of the cell, although the creation of unrepairable DNA double‐strand breaks is believed to be the lethal event. Modern radiobiology has come to recognize that cells not directly hit by ionizing events still show effects via the bystander mechanism. The exact mechanism of that remains unclear, but it can be mediated through gap junctional communication or through the transmission of soluble factors released into the extracellular space. At the tissue level, the ultimate response to IR events depends on the “4 R’s of radiobiology”: repair, repopulation, redistribution, and reoxygenation. Radiation dose response is believed to follow a linear no‐threshold model. Although initial damage seems to follow this pattern, a gap in the scientific literature remains on how repair and downstream effects are treated in the cell or tissue at the lowest exposure levels.
Nonionizing Radiation, Biological Effects of
Authors: Wood Andrew
Published: April 2006

Non‐ionizing radiation (NIR) refers to that part of the electromagnetic spectrum with a wavelength greater than approximately 100 nm. It is customary to include static electric and magnetic fields under the heading of NIR, and some also include ultrasound. When compared with ionizing radiation, there is a perception that NIR is intrinsically less dangerous (because it does notionize), so that the need for legislative control is less compelling. It should be emphasized that all forms of NIR, if present at a sufficiently high intensity, have the capacity to cause serious injury. It is perhaps fortunate that technologies employing NIR have developed in such a way that instances of serious injury are relatively rare and fatality virtually zero. The accepted hazards of most forms of NIR occur within a short time of exposure. The exception to this is ultraviolet radiation (UVR), particularly solar UVR, where risks of skin cancer and cataract have a stochastic nature and the diseases occur several years after exposure. The perception among sections of the wider community is that all forms of radiation, including NIR, can lead to disease in the long term, despite a lack of consistent evidence. This article reviews the nature of interactions of NIR with biological tissue, explains the rationale behind present‐day exposure limits, and explores some of the uncertainties that have led to the “Precautionary Principle” being invoked. It also briefly reviews some properties of NIR that have led to its use in diagnosis and therapy.
Biomaterials: An Overview
Authors: Seal Brandon L. , Panitch Alyssa
Published: April 2006

Biomaterials are materials of metallic, ceramic, polymeric, or composite origin that are used or that have been designed for use in medical devices or in contact with the body in order to augment, replace, or restore the function of diseased or damaged tissues or organs. Applications involving biomaterials range from load bearing orthopedic devices to degradable sutures to living skin equivalents. Although the types of materials used as biomaterials is diverse, most implanted biomaterials elicit a very similar inflammatory and foreign body response. In an attempt to minimize adverse biological responses and improve the performance of biomaterials at a tissue, cellular, and molecular level, current research in biomaterials has led to a paradigm change in which biomaterials consist of, mimic, or are designed to interact specifically with biological elements and systems. Continued adaptation of biomaterials design to biological responses will result in better performing devices that work with the body to promote tissue regeneration and healing.
Biomedical Engineering Education
Authors: Benkeser Paul
Published: April 2006

Educational programs in biomedical engineering have been under development for >40 years. The past decade has seen a significant increase in both the number of programs and student interest in those programs. This rapid growth has fueled a movement to establish a common vision of the knowledge and skills that all biomedical engineers need to possess. A partnership between industry, biomedical engineering educators, and learning science researchers is needed to ensure that this will be a shared vision and will enable students to be well prepared for careers in this field.
Biosurface Engineering
Authors: Molnar Peter , Hirsch‐Kuchma Melissa , Rumsey John W. , Wilson Kerry , Hickman James J.
Published: April 2006

Biological organisms are very complex and highly organized systems. One way biology achieves this high order of organization is the use of spatially and temporally controlled extracellular guidenance clues. Recent developments in surface chemistry, micro‐ and nanofabrication, and cell biology make it possible to recreate some of these organizational clues in a spatially controlled manner. Using these tools, active surfaces can be created that direct the behavior of cells in a controlled manner. In this article, the authors summarize the historical development of the field of cell patterning and give an overview of the available surface modification and patterning methods. They make a detailed comparison of the most commonly used techniques while listing their benefits and limitations as well as pointing out current difficulties that need to be overcome to make this methodology more applicable to real biomedical and biotechnological applications.
Biotelemetry
Authors: Ziaie Babak
Published: April 2006

In this article, several biotelemetry microsystems currently being developed in the academia and industry are reviewed.
Blind and Visually Impaired, Assistive Technology for
Authors: Y. J. Szeto Andrew
Published: April 2006

One of the most debilitating human conditions is blindness or severe visual impairment. Many assistive devices have been developed during the past decades to ameliorate the two primary challenges associated with this disability: access to reading material and independent mobility. This article presents an overview of the consequences of this impairment and examines the various technological aids currently available and under development to address these problems. This article discusses the consequences of blindness and severe visual impairment; assistive technology that facilitates access to written information; assistive devices that enhance independence in the activities of daily living; and mobility and navigational aids that enable persons who are blind or severe visual impaired to achieve safer and more independent travel. The article concludes with a prospective look at assistive technology likely to become available in the not too distant future.
Blood Pressure Measurement
Authors: Isik Can
Published: April 2006

Blood pressure is one fundamental vital sign, and its measurement is of great importance to medical professionals and the general public alike. This article describes direct and indirect methods of measuring blood pressure. There are many techniques of blood pressure measurement in the market, and more are being investigated in the laboratories and tested in the field. A number of these techniques are covered here, giving particular emphasis to the oscillatory techniques extensively employed in devices targeted for clinical use as well as those targeted for home use. Also included are limitations of different techniques, possible remedies to those limitations, and an analysis of the accuracy of a variety of blood pressure measurement devices.
Blood, Artificial
Authors: Woodcock Brian
Published: April 2006

This article reviews the importance of blood and discusses risks of banked blood, PFC emulsions and studies related to PFCs, as well as hemoglobin solutions.
Bone Cement, Acrylic
Authors: Li Chaodi , Zhou Yan
Published: April 2006

Bone cement has been widely used in orthopedic surgeries since Sir John Charnley first introduced the self‐curing bone cement for the fixation of artificial joints in 1958. Several important aspects of material characteristics of bone cement, including its material compositions, short‐ and long‐term mechanical properties are discussed in this article. This article aims to provide comprehensive information for the orthopedic community on cement applications.

The article is arranged in seven sections and begins with a brief introduction and description of bone cement compositions, followed by a section on cement setting procedure and cementing technique. Then, the thermal aspect (polymerization heat and potential bone thermal damage) and volumetric change effects (porosity and residual stress) are discussed. The final section focuses on the main mechanical properties of cement, including the static strength, fatigue failure, and viscoelasticity of bone cement. Finally, the article ends with a brief summary of potential research directions.
Bone Ununited Fracture and Spinal Fusion, Electrical Treatment of
Authors: Liboff AR
Published: April 2006

This article defines ununited fracture and discusses the electrical character of bone, direct current and electromagnetic osteogenesis, electric treatments, and electromagnetic devices.
Brachytherapy, High Dosage Rate
Authors: Das Rupak
Published: April 2006

Brachytherapy is a form of radiotherapy whereby a radioactive source is used inside or at short distance from the tumor. There are three different forms of brachytherapy: interstitial, intracavitary, and skin therapy. In interstitial brachytherapy, the radioactive sources are implanted inside and throughout the tumor volume; in intracavitary brachytherapy the sources are placed in the body cavities very close to the tumor; while in skin therapy the sources are placed on the skin surface. Conventionally, brachytherapy implants have delivered the radiation at a low dose rate (dose rates of <1 Gy/h). Low dose‐rate (LDR) interstitial implants can be temporary (meaning that the radioactive sources are left in place for a period of time, usually a few days, and then removed) or permanent (left in place without removal), while intracavitary implants are temporary. The advent of methods to deliver the dose at a much higher dose rates, in the range of 1–5 Gy/min, brought an increase in the use of brachytherapy. All high dose‐rate (HDR) brachytherapy treatments are temporary and treatments are administered using discrete fractions.
Cardiac Output, Thermodilution Measurement of
Authors: Trautman Edwin D. , D’ambra Michael N.
Published: April 2006

If a substance is introduced at a constant rate into the flowing bloodstream and allowed to “mingle” with the blood, then the measured steady‐state concentration of that substance downstream of the site of introduction is inversely proportional to the flow rate. If a small amount of the substance is introduced rapidly, then the concentration integrated over time is inversely proportional to flow rate. In thermodilution the indicator substance is heat (or cold) whose concentration is measured using a thermistor on a pulmonary artery catheter. The indicator is typically 10 mL of iced or room temperature saline introduced rapidly as a bolus into the right atrium, producing a temperature transient that rises rapidly and then decay exponentially. In practice, the indicator recirculates before the transient returns to baseline and an extrapolation needs ato be made. There are other practical considerations, such as indicator warming during injection, baseline temperature fluctuations, variations in curve shape, variation in thermal properties of blood, and anatomical abnormalities that can affect the accuracy and reproducibility of the measurement. All told, the accuracy is to within 2–7%, when compared to other measurement techniques. Continuous measurements are possible using a filament heater on the catheter to produce small thermal fluctuations and sophisticated signal processing to extract the signal from the background noise. Pulmonary artery catheters have many uses and are placed in patients for hemodynamic and cardiac assessments beyond cardiac output. Catheters and cardiac output computers are available from a number of manufacturers. The bolus thermodilution measurement of cardiac output is convenient and practicle and is considered the “gold” standard by which other techniques are compared.
Cell Counter, Blood
Authors: Zhang Yi , Neelamegham Sriram
Published: April 2006

This article discussed the basic principles of hematology with emphasis on humans. Enumeration of cell population distribution in peripheral blood is examined using optical, electrooptical and light scattering techniques. As seen, such experimental modalities can be automated and the resulting hematology analyzers can be used for clinical application. Even though the exact strategy of cell counting varies between various manufacturers of automated cell counters, performance standards for such instrumentation have been established by the National Committee for Clinical Laboratory Standard (NCCLS) and the International Council for Standardization in Hematology (ICSH). The parameters evaluated here include (1) accuracy in measurement within a single batch and between batches of blood samples; (2) carryover of parameters between consecutive samples; (3) linearity or the ability to get similar measurements when the sample is diluted to different levels before being read; and (4) clinical sensitivity or the specificity and efficiency with which flags are generated during analysis to detect abnormal readouts.
Chromatography
Authors: Edwards Thayne L.
Published: April 2006

Chromatography is the process of separating a mobile phase mixture into its individual components using the relative interactions of the components with a stationary phase. Chromatography is often used as a method of purification, even when the components are closely related. When used in conjunction with a concentration or mass‐based sensor, it can also be a power analytical method. This chapter explores the basic processes of the various types of chromatography and the closely related techniques of field‐flow fractionation (FFF) and electrophoresis. Some of the basic theory of chromatography will be given in terms of retention mechanism and separation performance. In addition, a description of the basic types of chromatography, electrophoresis, and FFF will be given in relation to their theory and application.
Codes and Regulations: Radiation
Authors: Thomadsen Bruce , Glasgow Glenn , Edwards Benjamin , Lieto Ralph
Published: April 2006

Several govermental agencies regulate radiation and radioactive meterials, each having a difference perspective of the problems to be addressed. An interested party is well advised to cinsult the most current verions of the regulations, which nowadays can be found on‐line. While particular regulations change very slowly in response to changing situations, the regulations as a whole change frequently. Regulations arise from recommendations from nationlal and international scientific and professional organizations, but are shaped by the governmental organization writing the regulation. A major division falls between regulations for ionizing and nonionizing radiations. For ionizing radiation, until currently, there was another division between radiation and radioactive materials generated by reactors and those from other accelerators, but the ssshape of the changes is yet to be seen. Many states have taken over much of the role of the U. S. Nuclear Regulatory Commission in their domain through agreements with that angency.
Colorimetry
Authors: Shen Li‐Jiuan , Mandel Richard , Shen Wei‐Chiang
Published: April 2006

Colorimetry is based on the observation that molecules absorb light. The wavelengths and efficiency of absorption depend on both the structure of the molecule and its environment, making absorption of light a useful tool for characterizing both small molecules and macromolecules. Colorimetric methods utilize these light‐absorbing spectral properties to measure the presence, concentration, or enzymatic activity of substances. Colorimetric methods have clinical applications primarily for the quantitative analysis of biological substances and enzymes or drugs and their metabolites in specimens using either their known spectral characteristics or their reactivity with other substances having known spectral characteristics. Colorimetry is also one of the commonly used detection methods in the development of modern analytical technologies, such as enzymed‐linked immunosorbent assays (ELISA) and microarray assays, in biomedical sciences.
Colposcopy
Authors: Selim Mostafa A. , Shalodi Abdelwahab D.
Published: April 2006

The history, the colposcope and the digital advances in the instrument is described. The clinical application of the colposcope in diagnosis and treatment of the neoplasia of the cervix is emphasised.The terminology used to explain the changes in the transformation zone of the cervix is explained.
Communication Devices
Authors: Cook Albert
Published: April 2006

Augmentative and alternative communication (AAC) systems supplement, but do not replace other modes of communication, such as speech, gestures, vocalizations, or facial expressions. The need for AAC, may be
congenital
(e.g., cerebral palsy or developmental disability) or a
cquired
. The severity of need varies from mild to moderate to severe based on physical, cognitive, and linguistic involvement. The overall prevalence from mild to severe for AAC needs is 0.2–0.6% of the total population. There are two basic communication needs that lead to the use of augmentative and alternative communication systems: conversation and graphics. These two needs differ in many important aspects. Conversational needs are those that would typically be accomplished using speech if it were available. The characteristics of AAC devices can be grouped into three major components: (1) control interface, (2) processor, and (3) activity output. The control interface links to a selection method, selection set, and an optional user display. Two selection methods are used in AAC systems. Direct selection is the fastest and easiest selection method to understand and use because the user merely chooses the one that he or she wants. Indirect selection is used to provide access for individuals who lack the motor skills necessary to use select directly and involves one or more intermediate steps between the user’s action and the entry of the choice into the device. Assessment of persons for AAC and training of them to develop skills are very important parts of a service delivery system.
Communication Disorders, Computer Applications for
Authors: Cress Cynthia J. , Green Jordan R.
Published: April 2006

This chapter provides an overview of the types of computer and technology applications used in the field of communication disorders. The introduction outlines the range of communication disorders for which technology has been applied. The main body of the article highlights current ways in which computer technology has been applied for administration, analysis of typical function, assessment, intervention, and assistive devices. Within each section, applications are discussed for speech, hearing, and language disorders. Each section concludes with benefits and limitations of computer technology for the type of application discussed. A final section outlines directions of future research and development in the areas of speech, hearing, language, and assistive devices.
Computed Tomography, Single Photon Emission
Authors: Fahey Frederic H. , Ziessman Harvey A.
Published: April 2006

Single photon emission computed tomography (or SPECT) provides a three‐dimensional (3D) representation of the
in vivo
distribution within a patient's body of a radiopharmaceutical that was given as part of a diagnostic nuclear medicine study. This chapter will devote most of its attention to the use of the rotating gamma camera.
Computers in the Biomedical Laboratory
Authors: Silverman Gordon
Published: April 2006

This article reviews the history of biomedical laboratory research and discusses the role of computers in the biomedical lab.
Contraceptive Devices
Authors: Kane Mollie
Published: April 2006

Contraceptives and contraceptive devices are possibly the most widely used medical devices today. In the United States, 42 million women, or 7 in 10 women ages 15–44, are currently sexually active and do not want to become pregnant (1). In 2002, 98% of women who had ever had intercourse had used at least one method of contraception. Ninety percent had used a condom at least once. Of reproductive age women (15–44 years), 62% were currently using contraception.
Coronary Angioplasty and Guidewire Diagnostics
Authors: Banerjee Rupak K. , Roy Abhijit Sinha , Back Lloyd H.
Published: April 2006

Percutaneous coronary transluminal angioplasty (PTCA) is an interventional procedure most widely used to revascularize diseased coronary vessels. Since its inception in 1964, modern‐day PTCA involves the use of cutting edge devices that have vastly improved the usefulness of this procedure, with minimal damage to coronary vessels such as left anterior descending, left circumflex, and right coronary arteries. In this article, the authors give an overview of key devices and instruments that have become synonymous with coronary angioplasty. Additionally, the authors present a summary of their past work on coronary diagnostics using customized guidewires, a key component of coronary angioplasty. Guidewires are commonly used to measure two hemodynamic indices, myocardial fractional flow reserve and coronary flow reserve, to evaluate the degree of success achieved in opening up a diseased (or blocked) coronary vessel. However, the presence of guidewire introduces an additional flow obstruction effect, which necessitates that some correction be applied to myocardial fractional flow reserve and coronary flow reserve. This process would enable estimation of true severity of coronary lesion, and its possible treatment using PTCA. This article provides these corrections through simple correlations that could be useful for diagnosis of focal coronary lesions under clinical settings.
Cystic Fibrosis Sweat Test
Authors: Warwick Warren J.
Published: April 2006

Cystic fibrosis (CF, cystic fibrosis of the pancreas, mucovisidosis) is an autosomal recessive genetic clinical condition that occurs in ∼1 in 2500 Caucasian newborn infants. The frequency ranges from ∼1:200 in genetically isolated populations to 1:30,000 in certain ethnic and racial groups. The measurement of the increased chloride in the sweat is the most reliable diagnostic test for the presence of two mutations of the CFTR mutation. This excessive sweat chloride is found in >98% of patients with the genetic potential to develop the clinical diseases associated with these CFTR mutations.