bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluators of image reconstruction algorithms
Authors: Herman Gabor T. , Yeung K. T. Daniel
Published: March 2007

An image reconstruction algorithm is supposed to present an image that contains medically relevant information that exists in a cross section of the human body. There is an enormous variety of such algorithms. The question arises: Given a specific medical problem, what is the relative merit of two image reconstruction algorithms in presenting images that are helpful for solving the problem? An approach to answering this question with a high degree of confidence is that of ROC analysis of human observer performance. The problem with ROC studies using human observers is their complexity (and, hence, cost). To overcome this problem, it has been suggested to replace the human observer by a numerical observer. An even simpler approach is by the use of distance metrics, such as the root mean squared distance, between the reconstructed images and the known originals. For any of these approaches, the evaluation should be done using a sample set that is large enough to provide us with a statistically significant result.

We concentrate in this paper on the numerical observer approach, and we reintroduce in this framework the notion of the Hotelling Trace Criterion, which has recently been proposed as an appropriate evaluator of imaging systems. We propose a definite strategy (based on linear abnormality‐index functions that are optimal for the chosen figure of merit) for evaluating image reconstruction algorithms. We give details of two experimental studies that embody the espoused principles. Since ROC analysis of human observer performance is the ultimate yardstick for system assessment, one justifies a numerical observer approach by showing that it yields “similar” results to a human observer study. Also, since simple distance metrics are computationally less cumbersome than are numerical observer studies, one would like to replace the latter by the former, whenever it is likely to give “similar” results. We discuss approaches to assigning a numerical value to the “similarity” of the results produced by two different evaluators. We introduce a new concept, called rank‐ordering nearness, which seems to provide us with a promising approach to experimentally determining the similarity of two evaluators of image reconstruction algorithms.
Superhigh image resolution for microwave imaging
Authors: Li Hsueh‐Jyh , Liu Ta‐Yung , Yang Sheng‐Hui
Published: March 2007

Algorithms for extrapolating the scattered field along the frequency direction and the azimuthal direction are developed and analyzed. Their effects on the image resolution for polar format processing and rectangular format processing are discussed. Simulation and experimental results show that extrapolation along the frequency direction does increase the range resolution. While extrapolation along the azimuthal direction improves the cross‐range resolution for small angle imaging, it does not improve image resolution of complex‐shaped objects for wide angle imaging. Both range and cross‐range resolutions can be improved simultaneously for small angle imaging using rectangular format processing if the angular interval and the resolution cells are suitably chosen. A promising application for the algorithms developed is in microwave dynamic imaging.
Resolution analysis of tomographic reconstruction of electron density profiles in the Ionosphere
Authors: Na Helen , Lee Hua
Published: March 2007

Traditionally, knowledge of the ionospheric electron density is obtained using Faraday rotation or differential Doppler techniques which measure total electron content in columns of the ionosphere. Conventional data processing can only image the electron density in the direction perpendicular to these columns, thereby forming one‐dimensional images. Because this data is proportional to line integrals through the region of interest, tomographic techniques may be used to reconstruct two‐dimensional electron density images. In this paper, the resolution limit of the image reconstruction process is analyzed in terms of limited‐angle tomography.
Chromatic edge detection: Idealization and reality
Authors: Lee Hsien‐Che
Published: March 2007

Chromatic edges are edges that correspond to large changes of red, green, and blue signals in unequal proportions. They are often, but not always, caused by changes in surface material. In this article, the theoretical and practical problems of chromatic edge detection are examined in detail.
Unsupervised estimation of speckle noise in radar images
Authors: Lee Jong‐Sen , Hoppel Karl , Mango Stephen A.
Published: March 2007

Speckle in radar images has the characteristic of a multiplicative noise. In this article, two unsupervised methods are introduced to estimate the speckle noise statistics using the mean and the standard deviation of small image blocks (4 × 4, or 6 × 6 pixels). Since most radar images contain many small homogeneous areas, a scatter plot of the standard deviation versus the mean can reveal the characteristic of the noise. The blocks from inhomogeneous areas have higher values for the standard deviation, and they are scattered above the main cluster. They are considered as outliers, and should be excluded in the statistical estimation. These two methods are designed for obtaining a linear fit in the scatter plot by ignoring outliers. Several synthetic aperture radar(SAR) images are used for illustration.
Investigations of the ionosphere by satellite radiotomography
Authors: Kunitsyn V. E. , Andreeva E. S. , Tereshchenko E. D. , Khudukon B. Z. , Nygrén T.
Published: March 2007

An overview of tomographic approach to remote sensing of ionosphere by radio waves is presented. Various methods, including diffraction, statistical, and ray radiotomography are discussed. The experimental procedures of satellite radiotomography are described. Results from satellite experiments in 1984–1993 are shown demonstrating the great possibilities of the radiotomographic method in ionospheric research.©1994 John Wiley & Sons Inc
Russian‐American tomography experiment
Authors: Foster J. C. , Buonsanto M. J. , Holt J. M. , Klobuchar J. A. , Fougere P. , Pakula W. , Raymund T. D. , Kunitsyn V. E. , Andreeva E. S. , Tereshchenko E. D. , Khudukon B. Z.
Published: March 2007

To intercompare various techniques used in reconstructing tomographic images, and to benchmark those results with direct observations obtained by the incoherent scatter technique, an experimental campaign and subsequent analysis program‐the Russian‐American Tomography experiment (RATE)‐were implemented in late 1993. Russian experiment teams from the Polar Geophysical Institute in Murmansk and Moscow State University joined with American investigators from the Phillips Laboratory and the Massachusetts Institute of Technology, and an array of four receiving stations was set up in the northeastern United States and in eastern Canada to obtain data for the tomographic reconstructions. Phase‐difference and total‐phase tomographic reconstruction techniques have been employed and are intercompared. The spatial/altitude distribution of ionospheric electron content was observed by the MIT Millstone Hill incoherent scatter radar that scanned the ionosphere in a plane parallel to the satellite overflights. We present preliminary reconstructions of the ionospheric structure observed during a severe midlatitude ionospheric storm that took place during the campaign. The drastic large‐scale changes in the ionospheric structure that accompanied the November 1993 storm were well observed by the two diagnostic techniques.©1994 John Wiley & Sons Inc
Imaging the ionosphere with the global positioning system
Authors: Hajj G. A. , Ibañez‐Meier R. , Kursinski E. R. , Romans L. J.
Published: March 2007

Observing the Global Positioning System with a satellite in low earth orbit in an occulting geometry provides a powerful means of imaging the ionosphere. Tomographic imaging of the ionosphere from space and ground is examined using singular value decomposition analysis. The resolution and covariance matrices are examined, and simulations are performed that indicate that space data are significantly more effective than ground data in resolving both horizontal and vertical structures, such as the E layer, can be probed with occultation data.©1994 John Wiley & Sons Inc
Nonlinear global and local document degradation models
Authors: Kanungo Tapas , Haralick Robert M. , Phillips Ihsin
Published: March 2007

Two sources of document degradation are modeled: (1) perspective distortion that occurs while photocopying or scanning thick, bound documents; and (2) degradation due to perturbation in the optical scanning and digitization process: speckle, blurr, jitter, and threshold. Perspective distortion is modeled by studying the underlying perspective geometry of the optical system of photocopiers and scanners. An illumination model is described to account for the nonlinear intensity change occurring across a page in a perspective‐distorted document. The optical distortion process is modeled morphologically. First, a distance transform on the foreground is performed; this is followed by a random inversion of binary pixels in which the probability of flip is a function of the distance of the pixel to the boundary of the foreground. Correlating the flipped pixels is modeled by a morphological closing operation.©1994 John Wiley & Sons Inc
High‐resolution restoration of dynamic image sequences
Authors: Yu‐Su Wen , Kim Seung P.
Published: March 2007

We investigated an approach to reconstructing high‐resolution images from dynamic image sequences using local spectral analysis. High‐resolution reconstruction from linearly shifted multiple static image frames has previously been studied, in which the aliasing relationship between the spectrum of the original signal and the DFTs of shifted and sampled signals is exploited. In the high‐resolution reconstruction of dynamic image sequences, difficulties occur as a result of nonuniform shifts in the frames. We use loca spectral analysis to achieve high‐resolution reconstruction by overlapped block decomposition and motion compensation. For each block image in a reference frame in the sequence, motion estimation and subpixel registrations are performed against adjacent frames. High resolution reconstruction is performed on such motion‐compensated block‐image sequences. For some blocks containing motion boundaries, high resolution reconstruction is difficult; a new scene emerges or disappears producing inconsistent information. An interpolation technique is used in such blocks to generate the number of pixels consistent with other high‐resolution blocks. The flower‐garden image sequence is used for the computer simulations. The quality of the restored images are very encouraging; the aliasing effects in the original frames are significantly reduced and sharper edges are produced. The overall procedure to generate such higher‐resolution images from a dynamic image sequence is described in detail. The result can be applied to various image sequence restoration applications including up‐conversion of conventional video signals.©1994 John Wiley & Sons Inc
Conformal therapy using maximum entropy optimization
Authors: Sandham William A. , Yuan Yong , Durrani Tariq S.
Published: March 2007

Conformal therapy offers considerable advantages over conventional radiotherapy treatment, because it has the potential for matchingalmost exactlythe delivered dose distribution to the prescribed dose distribution. Associated (inverse) treatment planning methods address a constrained linear optimization problem. In this article, a method based on maximizing the total entropy of the beam profiles is developed. Maximum entropy optimization constrains the computed dose to be within well‐defined tolerances of the prescribed dose, and has advantages of robustness, fast convergence, and high accuracy. For the work reported here, it is assessed using clinically prescribed irregular target dose volumes based on magnetic resonance imaging and computed tomography images. Results are shown for a two‐dimensional, homogeneous absorption, primary dose computation model, to illustrate the feasibility of the approach; however, the method may be extended to accommodate a more general three‐dimensional model, including inhomogeneities and scatter dose contributions. Optimization of beam offset for a regular angular displacement of beams is also considered, with particular regard to implications on total beam energy, entropy, and computation time.
Methodologic considerations for spiral k‐space functional MRI
Authors: Noll Douglas C.
Published: March 2007

Magnetic resonance imaging has recently been developed as a tool to image brain function based on regional changes in blood oxygenation. In this article, we examine the methodologic considerations for functional brain mapping using the spiral k‐space acquisition technique. Gradient design and image reconstruction methods as well as considerations for the selection of imaging parameters are presented. Several sources of image artifacts, along with artifact compensation strategies, are examined. Functional maps of activation in primary motor cortex are usd to demonstrate the effect of image parameter selection and of artifact compensation procedures. These results demonstrate that the spiral k‐space acquisition technique is a rapid, flexible, and robust method for imaging brain activity.
Comparison of T2*‐weighted sequences for functional MRI
Authors: Hu Xiaoping , Erhard Peter , Le Tuang Huu , Kim Seong‐Gi , Menon Ravi , Andersen Peter , Adriany Gregor , Strupp John P. , Uǧurbil Kâmil
Published: March 2007

Several sequences, including conventional gradient‐echo sequence (e.g., FLASH), gradient‐echo echo‐planar imaging (EPI), T2* prepared ultrafast gradient echo technique (TurboFLASH), and T2*‐weighted spiral sequence, are currently used for T2*‐weighted functional magnetic resonance imaging. This paper presents a comparison of FLASH, gradient‐echo EPI, and T2*‐prepared TurboFLASH. Experimental results have demonstrated that these sequences have different susceptibility to physiologic fluctuation, which is likely the dominant source of noise. EPI images exhibit the lowest relative fluctuation, while images obtained by FLASH and TurboFLASH, respectively, display similar relative fluctuation. Functional maps generated using these sequences are comparable but exhibit different sensitivity to activation from large vessels. Consequently, interpretation of activation results from various maps should take into account the difference in the sequences.
On the use of temporal correlation coefficients for magnetic resonance mapping of functional brain activation: Individualized thresholds and spatial response delineation
Authors: Kleinschmidt Andreas , Requardt Martin , Merboldt Klaus‐Dietmar , Frahm Jens
Published: March 2007

Functional activation of the human visual and motor system was studied by magnetic resonance imaging (MRI) at 2.0 T using dynamic series of oxygenation‐sensitive gradient‐echo images at high spatial resolution. Activation maps were computed by correlating signal intensity time courses with a reference waveform on a pixel‐by‐pixel basis. Although this strategy readily demonstrates stimulus‐related functional cooperativity of activated regions in thresholded maps of correlation coefficients, intertrial variability in the underlying distributions of correlation coefficients precludes the use of correlation coefficients as direct thresholds for defining activation. Because stimulus‐related effects emerge as positive deviations from an otherwise symmetric distribution of correlation coefficients, invariance against intertrial differences as well as adequate visualization of activated areas may be achieved by the following procedure. First, a symmetrized noise distribution is reconstructed from the actual activation map that allows rescaling of correlation coefficients into percentile ranks with respect to the integral of the noise distribution. Second, a high percentile rank (or correspondingly low error probability) can be used as threshold to define primary sites of activation with high specificity. And third, the spatial extent of activation may be delineated by adding directly neighboring pixels with lower values provided their correlation coefficients are high enough to contribute to the positive deviation from the noise distribution. The outlined approach yields robust activation maps but still awaits a more thorough statistical treatment of activation in MRI correlational mapping.
Cognitive task design for FMRI
Authors: Worden Michael , Schneider Walter
Published: March 2007

The quality of functional magnetic resonance imaging (FMRI) data is determined by the quality of the scanning and the control of cognitive behavior of the individual being scanned. This report describes cognitive task design methodology. It is suggested that mapping the stages of cognitive processing is a technically achievable goal with current technology. The behavioral paradigms in FMRI are categorized into technique development and brain mapping paradigms. Technique development paradigms are used to tune scanning parameters with tasks such as visual mapping, motor responding, and language processing. Brain mapping paradigms generally examine uncharacterized areas of cortex. Three stages of brain mapping are described, including: (1) determining the number, location, and stability of active areas; (2) determining the topology and replication of areas; and (3) determining the exogenous/endogenous differentiation of areas. Issues of condition sequencing of tasks within and between trials, statistical analysis, and practical FMRI running are described.
Functional magnetic resonance imaging of language cortex
Authors: Binder Jeffrey R.
Published: March 2007

This review examines recent functional magnetic resonance imaging (FMRI) studies of language cortex. Included are activation studies involving listening to speech, reading, word generation, semantic categorization, and verbal working memory. Where possible we compared FMRI results with similar data obtained using positron emission tomography. Several applications of language FMRI in neurologic patients are presented. Methodologic issues concerning task design are discussed from the perspective of cognitive neuroscience. These issues include the validity of “covert” responses, selection of control tasks, consideration of practice effects, and interpretation of “rest” conditions. FMRI has great potential to clarify the neurophysiologic basis of human language, although this potential remains largely unexplored.
Generalized cross‐validation as a stopping rule for the Richardson‐Lucy algorithm
Authors: Reeves Stanley J.
Published: March 2007

The Richardson‐Lucy (R‐L) algorithm has been widely used to restore degraded astronomical images. This algorithm is nothing more than the expectation‐maximization (EM) algorithm applied to Poisson data. The R‐L method is iterative in nature and converges to a (possibly local) maximum of the likelihood function. Unfortunately, because of the ill‐conditioned nature of the problem, this maximum likelihood estimate may actually be a very poor restoration. One way to prevent degradation of the restoration is to stop the iteration before it reaches convergence. A number of methods have been proposed for determining the optimal stopping point‐the point that provides the best trade‐off between restoring the image and amplifying the noise. Cross‐validation (CV) has recently been proposed as an advantageous method for determining the optimal stopping point. We propose a different form of CV based on generalized cross‐validation (GCV) that overcomes some of the difficulties of CV. We derive a GCV‐based criterion for the R‐L algorithm that can be efficiently evaluated at each iteration. We present examples displaying the power of the stopping rule and discuss the abilities and shortcomings of the method.
Bystander killing of breast cancer MCF‐7 cells by MDA‐MB‐231 cells exposed to 5‐fluorouracil is mediated via Fas
Authors: Chhipa Rishi Raj , Bhat Manoj Kumar
Published: March 2007

The major drawback with cancer therapy is the development of resistant cells within tumors due to their heterogeneous nature and due to inadequate drug delivery during chemotherapy. Therefore, the propagation of injury (“bystander effect” (BE)) from directly damaged cells to other cells may have great implications in cancer chemotherapy. The general advantage of the bystander cell killing phenomenon is the large therapeutic index that can be achieved. Experiments suggest that this phenomenon is detected in radiation therapy as well as in gene therapy in conjunction with chemotherapy. In the present study, we developed an original in vitro model dedicated to the exploration of bystander cytotoxicity induced during breast carcinoma chemotherapy. In brief, we investigated this perpetuation of injury on untreated bystander MCF‐7 breast cancer cells which were coplated with 5‐fluorouracil (5‐FU)‐treated MDA‐MB‐231 breast cancer cells. To achieve this goal, a specific in vitro coculture model which involved mixing of aggressive MDA‐MB‐231 breast cancer cells with enhanced green fluorescent protein (EGFP) expressing stable clone of non‐metastatic MCF‐7 breast cancer cells (MCF‐EGFP), was used. A bystander killing effect was observed in MCF‐EGFP cells cocultured with MDA‐MB‐231 cells pretreated with 5‐FU. The striking decrease in MCF‐EGFP cells, as detected by assaying for total GFP intensity, is mediated by activation of Fas/FasL system. The implication of Fas in MCF‐EGFP cell death was confirmed by using antagonistic anti‐FasL antibody that reverses bystander cell death by blocking FasL on MDA‐MB‐231 cells. In addition, inhibition of CD95/Fas receptor on the cell surface of MCF‐EGFP cells by treatment with Pifithrin‐alpha, a p53 specific transactivation inhibitor, partially abrogated the sensitivity of bystander MCF‐EGFP cells. Our data, therefore, demonstrates that the Fas/FasL system could be considered as a new determinant for chemotherapy‐induced bystander cell death in breast cancers. J. Cell. Biochem. J. Cell. Biochem. 101: 68–79, 2007. © 2007 Wiley‐Liss, Inc.
Excited state properties, fluorescence energies, and lifetime of a poly(fluorene‐pyridine) copolymer, based on TD‐DFT investigation
Authors: Chidthong Rungtiwa , Hannongbua Supa , Aquino Adelia J. A. , Wolschann Peter , Lischka Hans
Published: March 2007

The structural and electronic properties of the fluorene‐pyridine copolymer (FPy)n, (n = 1–4) were investigated theoretically by means of quantum mechanical calculations based on density functional theory (DFT) and time‐dependent DFT (TD‐DFT) using the B3LYP functional. Geometry optimizations of these oligomers were performed for the ground state and the lowest excited state. It was found that (FPy)n is nonplanar in its ground state, whereas a more pronounced trend toward planarity is observed in the S1 state. Absorption and fluorescence energies have been extrapolated to infinite chain length making use of their good linearity with respect to 1/n. An extrapolated value of 2.64 eV is obtained for vertical excitation energy. The S1←S0 electronic excitation is characterized as a highest occupied molecular orbital to lowest unoccupied molecular orbital transition and is dominating in terms of oscillator strength. Fluorescence energies and radiative lifetime were calculated as well. The obtained results indicate that the fluorescence energy and radiative lifetime of (FPy)n are 2.16 eV and 0.38 ns, respectively. The decrease of fluorescence energy and radiative lifetime with the increase in the chain length is discussed. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Current status of homogeneous enzyme immunoassays
Authors: Nakamura Robert M. , Robbins Bruce A.
Published: March 2007

Recent advances in homogeneous enzyme immunoassays (EIAs) are discussed. EIA methods have been developed with comparable sensitivity to those of radioimmunoassay (RIA). EIAs have become established in many clinical laboratories and are generally being employed for: 1) homogeneous assay of low molecular weight compounds such as drugs and antibiotics present in biological samples at relatively high concentrations, 2) qualitative and semiquantitative assays for viral, bacterial, fungal, and parasitic antigens and antibodies, 3) tissue immunohistochemical localization of antigens and antibodies, and 4) alternatives to RIA in smaller laboratories. This paper discusses the principles and applications of newer homogeneous assays such as avidin‐biotin enzyme, hybrid antibody, insoluble sub state and cloned enzyme donor, and electrochemical immunoassays. Future instrumentation for EIAs with the use of biosensors is also discussed.
Performance of the tandem ICON strep A® enzyme immunoassay system for detection of group a streptococci from oropharyngeal swabs
Authors: Kellogg James A. , Bankert David A. , Levisky John S.
Published: March 2007

The Tandem ICON Strep A® (TISA Hybri‐tech, Inc.) was compared to culture for detection of group A streptococci, using throat swabs obtained from patients with symptoms of pharyngitis. Each swab was first inoculated to a 5% sheep blood agar plate and then tested for streptococcal antigen using the TISA. Cultures were incubated anaerobically at 35°C for 36 to 48 hours unless positive following overnight incubation. Group A streptococci were recovered in culture and serologically identified from 163 (21.0%) of the 776 swabs processed. The sensitivity and specificity of the TISA were 76.7% and 96.4%, respectively, whereas the predictive values of positive (PVP) and negative (PVN) results were 85.0% and 94.0%, respectively. However, TISA specificity ranged from 93.6% in one of 3 lots tested to 99.1% in another (P < 0.005). The PVP of the former lot was 76.3%, whereas that of the latter was 95.6% (P < 0.005). The relative lack of sensitivity and lot‐to‐lot variation observed with the TISA in this study indicate that the product is not a suitable alternative to a competently performed throat culture.
Impaired interleukin‐2 production by t‐lymphocytes in polycythemia vera
Authors: Paul Cassandra C. , Baumann Michael A.
Published: March 2007

T‐lymphocyte function was investigated in a group of eight patients with polycythemia vela (PV) and 13 normals. Responsiveness of T‐cells to stimulation by mitogen was significantly impaired in the PV patients (p = .02). Analysis of immune cell subpopulation composition by assessment of cell surface phenotype did not reveal imbalances that could account for impaired T‐cell proliferative ability in PV patients. Addition of recombinant human interleukin‐1 to PV mononuclear cell cultures did not enhance proliferative ability.

Addition of recombinant human interleu‐kin‐2 to cultures had no effect on maximum mitogen stimulation in normals but significantly improved responses in PV patients (p < .02), correcting them to normal levels. Measurement of interleukin‐2 production by stimulated cultured mononuclear cells confirmed subnormal IL‐2 production by PV T‐cells (p < .00005). Impaired IL‐2 production could conceivably contribute to the pathogenesis of PV by limiting the ability of IL‐2‐dependent cells to regulate hematopoiesis.
Expression of the cd4 molecule on acute nonlymphocytic leukemia (anll) cell lines
Authors: Neudorf Steven , Delaat Cynthia , Jones Marilyn , Neudorf Steven
Published: March 2007

Mature and immature monocytes express the CD4 molecule similar to that expressed on lymphocytes. Since monocytes and cells of myeloid lineage are derived from a common progenitor, we studied a panel of nine myeloid leukemia cell lines for the expression of the CD4 molecule. We found that six of nine myeloid leukemia cell lines (U937, KG1‐B, HL‐60, THP‐1, HEL 92.1.7, KMOE) expressed CD4, the exceptions being the erythroleukemia line K562, myeloblast line KG1‐REV, and megakaryocytic line, CHRF‐288. SDS‐PAGE analysis of HL‐60 cells immunoprecipitated with OKT4 showed the presence of a 55kd molecule similar in weight to that seen on lymphocytes. These data suggest that some myeloid progenitor cells express the CD4 molecule and that the CD4 may have a broader distribution within hematopoietic cells.
Ca 72‐4 radioimmunoassay for the detection of the tag‐72 carcinoma‐associated antigen in serum of patients
Authors: Gero Eva J. , Melsheimer Richard , Colcher David , Ferroni Patrizia , Giani Silvia , Schlom Jeffrey , Kaplan Paul , Giani Silvia
Published: March 2007

Monoclonal antibody (MAb)B72.3 has been used to detect the presence of TAG‐72 in the serum of carcinoma patients. We have developed new anti‐TAG‐72 MAbs and have selected one of these, CC49, as the “catcher” MAb with 125I–B72.3 as the detecting antibody in a double‐determinant immunoradiometric assay. This combination enabled the development of a sequential assay (designated CA 72‐4) that showed optimal quantitative properties as demonstrated by such parameters as linear dose‐response, high reproducibility, and lack of serum‐matrix and “hook‐back” effects.

Only 3.5% of 744 normal sera and 6.7% of 134 sera from patients with benign gastrointestinal diseases had TAG‐72 levels greater than 6 U/ml. Approximately 40% of 303 patients with gastrointestinal malignancies had serum TAG‐72 levels of greater than 6 U/ml (55% of the patients with advanced disease). Thirty‐six percent of patients with adenocarcinomas of the lung and 24% of patients with ovarian cancer (53% stage IV patients) also had elevated serum TAG‐72 levels.

A poor correlation was found between the carcinoembryonic antigen (CEA) and TAG‐72 values of sera obtained from gastric cancer patients. Thirty‐four percent of CEA negative cases were scored positive in the CA 72‐4 assay, suggesting the complementarity of the CA 72‐4 assay to CEA assays in the analysis of sera from patients with certain malignancies.
Natural killer cytotoxicity in the diagnosis of immune dysfunction: Criteria for a reproducible assay
Authors: Whiteside Theresa L. , Bryant John , Herberman Ronald B. , Day Roger
Published: March 2007

Current evidence indicates that natural killer (NK) cells, which are large granular lymphocytes that mediate non‐major histocompatibility complex (MHC)‐restricted cytotoxicity and antibody‐dependent cytotoxicity and that are involved in multiple regulatory, developmental, and immunologic processes, are important in health. Immunodeficiency states presenting with low NK activity are often associated with malignancies, chronic viral infections, or autoimmune diseases. Monitoring of NK function appears to be indicated as an aid to diagnosis, prognosis, and follow‐up after therapy. Reliable performance of NK assays in a clinical laboratory requires that uniform criteria be established and followed for the acceptability of results. Statistical analysis of daily variability can be of great assistance in identifying and tracking sources of error, but routine statistical adjustments are not generally advisable. The quality control program described here provides a degree of assurance that this cytotoxicity assay can be dependable whether performed at one time point or serially. The successful implementation of this program requires laboratory resouces, biostatistical support, and interpretative skills, all of which are available in a modern clinical laboratory.
A sandwich enzyme immunoassay for detecting and measuring alzheimer's disease‐associated proteins in human brain tissue
Authors: Ghanbari Hossein A , Ghanbari Hossein A , Kozuk Terry , Miller Barney E. , Riesing Sue
Published: March 2007

A simple, fast, and reliable immunoassay has been developed to detect and measure Alzheimer's disease‐associated proteins (ADAPs) in human brain tissue. This assay, called ALZ‐EIA (brain), was developed for Abbott's quantum system, in which 1/4‐in. beads are used as solid phase. The beads were coated with polyclonal IgG purified from sera obtained from rabbits immunized with a highly enriched Alzheimer's disease brain protein fraction for ADAP. The antigen (ADAP) is effectively captured by the polyclonal IgG coated on the beads. ALZ‐50 (a mouse monoclonal IgM) is used as the detection antibody, and bound ALZ‐50 is subsequently quantified by a horseradish peroxidase‐linked goat antimouse IgM and appropriate substrate. The assay is linear up to 0.5 absorbance units (r = 0.9), reproducible (CV less than lo%), sensitive, and specific. With preformulated reagents and standard supplies, the assay is simple and rapid; 120 data points can readily be generated in about 4 hr.
Effectiveness of testing for anti‐dna and the complement components ic3b, bb, and c4 in the assessment of activity of systemic lupus erythematosus
Authors: Clough John D. , Chang Rose K.
Published: March 2007

Seventy‐one patients with systemic lupus erythematosus (SLE), seen in an outpatient setting for follow‐up evaluation during a 3‐mo period, were tested (in addition to routine lupus monitoring studies) with enzyme immunoassays (EIAs) for anti‐DNA, iC3b, and factor Bb to determine the relationship of these test results to disease activity. SLE activity was scored by four previously reported scoring systems, and six patients were identified as active by all four systems. We found that the EIA for anti‐DNA was the best indicator of disease activity and that iC3b and Bb were not informative for this purpose in this group of patients. Mean iC3b levels were higher in a subset of seven patients with past biopsy evidence of severe (WHO class IV) glomerulonephritis than in the rest of the study population, even though none of these patients had active disease at the time of this study.
Precision of the islet‐cell antibody assay depends on the pancreas
Authors: Landin‐Olsson M.
Published: March 2007

Several workshops attempting to standardize the islet‐cell antibody (ICA) assay have demonstrated marked but unexplained inter‐laboratory variation. In this study, the effect of using 10 different pancreata to quantitate ICA in a standardized two‐color immunofluorescence test within the same laboratory was evaluated. Sera from 11 recent‐onset insulin‐dependent diabetic patients and one healthy control were analyzed. The negative control serum was recorded as ICA negative in all 10 pancreata. The ICA end‐point titers varied, with 1.1‐2.4 titration steps in standard deviations in the 10 different pancreata. The interassay variability within the same pancreas was 0.6‐0.9 titration steps and therefore could not alone explain the interpancreatic variation. The end‐point titers in the different pancreata were highly correlated (rs = 0.71‐1.0), supporting the hypothesis that the pancreatic tissue strongly influences the ICA levels. A quality index was developed for selection of pancreata with qualities for ICA analyses. The international ICA standard serum used to express the results in Juvenile Diabetes Foundation units diminished the interpancreatic variability.
Cholesterol oxides and carcinogenesis
Authors: Morin Robert J. , Hu Bing , Peng Shi‐Kaung , Sevanian Alex
Published: March 2007

Experimental evidence indicates a relationship between cholesterol α‐epoxide and skin cancer, and exposure of skin fibroblasts to ultraviolet radiation enduces formation of significant levels of this oxide. Colon cancer is also etiologically linked to cholesterol oxidation products. Higher than normal levels of cholestanetriol have been found in patients with colon cancer and also in those with precancerous disorders such as adenomatous polyps and ulcerative colitis. Higher than normal levels of cholesterol α‐epoxide have been found in breast fluid aspirates of women with benign breast disease, with or without atypical hyperplasia of the epithelium, and this may be a factor in the increased incidence of breast cancer associated with hyperplasia. Similarly, the observed increased levels of cholesterol α and β‐epoxides in prostatic fluid of men with benign prostatic hypertrophy may be associated with subsequent development of prostate cancer.

Cholesterol α‐epoxide has been found to be mutagenic to fibroblasts in culture and to induce morphological transformation in hamster embryo cells and in mouse C3H cells. 25‐Hydroxycholesterol and 20α‐hydroxycholesterol are potent suppressors of generation and proliferation of tumor‐specific cytotoxic T lymphocytes.

Although investigations into the role of cholesterol oxidation products in cancer are still in the early stages, evidence to date indicates a potentially significant role in the induction of some types of cancer.
Detection of group a streptococci by aerobic culture and a new simplified immunoassay in three pediatric practices and a hospital laboratory
Authors: Kellogg James A. , Bankert David A. , Schonauer Thomas D. , Landis Robert C. , Nussbaum Allen S. , Levisky John S.
Published: March 2007

Duplicate throat swabs for detection of group A streptococci were collected in three pediatric offices from 1,035 patients with symptoms of pharyngitis. In the collecting office and in the hospital laboratory, one swab from each patient was first inoculated to sheep blood agar (incubated at 35°C aerobically for 2 days) and then tested for group A streptococcal antigen by using the SMART enzyme immunoassay technique (New Horizons Diagnostics Corp) incubated for up to 24 hours. Group A streptococci were recovered in culture (from one or both swabs) and serologically identified from 444 (42.9%) of the patients. Pediatric offices numbers 1, 2, and 3 detected 84.4%, 84.6%, and 82.2%, respectively, of their patients who had positive cultures (in the office and/or laboratory) by using their own culture system and 82.6%, 71.1%, and 84.9%, respectively, of these same patients by using the SMART technique. In the laboratory, SMART test sensitivity and specificity were 71.4% and 98.7%, respectively, after 5 minutes of test incubation. However, SMART test sensitivity improved to 86.5% after overnight incubation of the immunoassay and to 91.3% if the data from one defective lot of seven SMART production lots studied were excluded. SMART test results which are negative after 5 minutes of incubation should therefore be confirmed both by reincubation of the antigen test up to 24 hours and by culture.
Evaluation of hiv p24 antigen, beta2‐microglobulin, neopterin, soluble cd4, soluble cd8, and soluble interleukin‐2 receptor levels in patients with aids or aids‐related complex treated with 2′,3′‐dideoxyinosine (ddl)
Authors: Reddy Mohan M. , McKinley George F. , Grieco Michael H.
Published: March 2007

Circulating HIV P24 antigen, beta2‐microglobulin, neopterin, soluble CD4, soluble CD8, and soluble interleukin‐2 receptor were measured in 13 zidovudine‐intolerant patients (8 with ARC and 5 with AIDS) treated with dideoxyinosine (ddI). Measurements were made at baseline and at several intervals during therapy. Mean levels of HIV P24 antigen decreased early and significantly (P<0.01) after 2 weeks of ddI administration and remained low at weeks 8 and 12. In addition, mean SCD8 levels decreased late and significantly (P<0.02) after 16 weeks of ddI treatment and remained low at 24 weeks. In contrast, ddI administration had no substantial effect on mean levels of beta2‐microglobulin, neopterin, soluble CD4, and soluble interleukin‐2 receptor. ddI administration appears to have been associated with early reduction of HIV P24 antigen levels and later reduction of SCD8 mean levels in these patients.
Microtiter plate assay for phagocyte‐derived Taurine‐chloramines
Authors: Witko Véronique , Nguyen Anh Thu , Descamps‐Latscha Béatrice
Published: March 2007

Despite their potential importance, the role of phagocyte‐derived chloramines (“longlived oxidants”) has not yet been investigated in inflammatory or infectious diseases. We have developed a sensitive spectrophotometric microtiter plate assay for chloramines based on their capacity to oxidize potassium iodide (Kl). Consistant levels of endogenous chloramines were detected in normal human polymorphonuclear neutrophil (PMN) supernatants after stimulation by phorbol myristate acetate (PMA) or opsonized zymosan. Exogenous taurine strongly enhanced chloramine secretion and was used to quantify the chlorinating potential of PMN. Taurine‐chloramines were also detectable in monocyte supenatants, although in smaller amounts. The specificity of the KI assay was assessed both in terms of effect of compounds inhibiting (KBr) or interacting with (sodium azide and catalase) chloramine formation and by showing that PMN from patients with chronic granulomatous disease, due to a hereditary lack of oxidative response capacity, were unable to produce chloramines. Taurine‐chloramine levels secreted by PMA (but not zymosan)‐stimulated PMN were closely related to the cellular luminol‐amplified chemiluminescence (CL) responses although the CL assay failed to detect chloramines in PMN supernatants. We consider that this KI assay should be of use in studying the role of long‐lived phagocyte‐derived oxidants in clinical medicine.
Cross‐reactivity of highly purified okadaic acid (OA), synthetic, spiroketal east sphere of OA and ciguatoxin
Authors: Hokama Y. , Hong T. W. P. , Isobe M. , Ichikawa Y. , Yasumoto T.
Published: March 2007

This study presents data from the crossreactivity analysis of purified ciguatoxin (CTX), okadaic acid (OA), and the East sphere or Fragment B‐C of OA with their homologous antibodies, monoclonal antibodies to ciguatoxin (MAb‐CTX) and okadaic acid (MAb‐OA). The test system used was the stick enzyme immunoassay. MAb‐CTX gave peak titers of 1.5ng, 10ng and 50ng respectively for CTX, East sphere and OA. Competitive inhibition analysis showed that 4ng purified CTX blocked completely MAb‐CTX reaction with crude CTX, OA and East sphere of OA blocked at similar concentrations (approximately 50ng). The activity with MAb‐OA in the homologous system with OA and East sphere was insignificant. This may be attributable to the improper concentrations used. The cross‐reactivity between MAb‐CTX with OA and its Fragment B‐C may cause difficulty in the test system in its application to assess toxic fish due to ciguatoxin.
Heat inactivation of bovine serum used for blockade in immunoenzymatic assay is associated with spurious fall on the titers of anticardiolipin antibodies in primary antiphospholipid syndrome sera
Authors: Nava Arnulfo , Bañales José L. , Reyes Pedro A.
Published: March 2007

Anticardiolipin antibodies (ACA) were evaluated using enzyme‐linked immunosorbent assay (ELISA) with and without heat inactivation of bovine serum used for plastic surface blockade. Untreated sera samples from primary antiphospholipid syndrome patients (PAS) and healthy blood donors (HBD) were tested. A significant decrease of ACA liters of PAS sera occurred with inactivated bovine serum blockade ELISA when compared with basal ELISA. In HBD sera there was no significant change. Probably, as happens with normal human serum, heating for normal bovine serum produces an increase in ACA titers. This bovine ACA may react with cardiolipin, and when human samples are added, they find antigen sites occupied, resulting in a spurious decrease of ACA titers. © 1993 Wiley‐Liss, Inc.
Expression of cell adhesion molecules in the salivary and lacrimal glands of Sjogren's syndrome
Authors: Saito Ichiro , Terauchi Kumiko , Shimuta Misa , Nishiimura Satoshi , Yoshino Kenichi , Takeuchi Tsutomu , Tsubota Kazuo , Miyasaka Nobuyuki
Published: March 2007

We attempted to determine whether cell adhesion molecules, including vascular cell adhesion molecule‐1 (VCAM‐1), intercellular adhesion molecule‐1 (ICAM‐1), and E‐selectin (endothelial‐leukocyte adhesion molecule‐1; ELAM‐1), are involved in the lymphoid cell infiltration of the salivary and lacrimal glands in Sjogren's syndrome (SS) patients.

Both immunohistochemical analysis and the reverse‐transcripts polymerase chain reaction (RT‐PCR) were used to analyze the expression of VCAM‐1, ICAM‐1, ELAM‐1, very late antigen 4 (VLA‐4 [α4, β1]), lymphocyte function‐associated antigen‐1 (LFA‐1), interferon‐γ (IFN‐γ), tumor necrosis factor (TNF), and interleukin‐1 β (IL‐1β).

Immunohistochemical analysis of salivary gland biopsies from SS patients showed a marked expression of VCAM‐1 and ICAM‐1 in the venules surrounded by infiltrated CD4+ CD45RO+ T cells. E‐selectin was expressed on vascular endothelium with weak intensity. Increased levels of VCAM‐1, ICAM‐1, IFN‐γ, and IL‐1β mRNA were demonstrated by RT‐PCR, whereas E‐selectin mRNA were weakly expressed in SS iacrimal and salivary gland tissues. This is in contrast with strong expression of ELAM‐1 in IL‐1β‐stimulated human umbilical vascular endothelial cells (HUVEC) in vitro.

Cytokine‐mediated up‐regulation of VCAM‐1 and ICAM‐1 that facilitates the recruitment of VLA‐4 and LFA‐1 expressing T cells might contribute to lymphoid cell infiltration in the salivary and lacrimal glands in SS. © 1993 Wiley‐Liss, Inc.
Chemiluminographic detection of von Willebrand factor multimeric composition
Authors: Wen Long T. , Smolec Jo Marie , Coughlin Jan , McPherson Richard A.
Published: March 2007

Diagnosis of von Willebrand's disease (vWD) requires quantitation of von Willebrand factor (vWF) in plasma plus qualitative assessment of the vWF multimers according to molecular size ranges. Characterization of vWF multimeric size distributions is typically done using sodium dodecyl sulfate‐agarose gel electrophoresis (SDS‐AGE) followed by immunoblotting in the gel with radiolabeled antibody against vWF and autoradiographic exposure. We applied a western blot technique to vWF multimeric analysis. It included SDS‐AGE, electroblotting onto a membrane, and chemiluminescent detection using rabbit anti‐human vWF as primary antibody and goat anti‐rabbit IgG as secondary antibody conjugated with horseradish peroxidase. Using this method, 18 to 20 vWF multimers were regularly resolved in normal plasma with exposure times of 2 to 4 sec compared to 4 hr or longer by autoradiography. Sensitivity of detection was at least 4‐fold enhanced by chemiluminescence compared to radiolabel. Specificity of the assay was confirmed by analysis of plasma samples known to be deficient to different degrees in the larger vWF multimers. The chemiluminographic assay for vWF multimers is superior to the autoradiographic one because it is more sensitive, avoids use of radioactivity, and has shorter total assay time (under 2 days versus five radiolabel). © 1993 Wiley‐Liss, Inc.
Evaluation of reference ranges for fatty acids in serum
Authors: Sera Ronald K. , McBride James H. , Higgins Sharon A. , Rodgerson Denis O.
Published: March 2007

Long chain fatty acid fractionation has become a valuable tool in the management of patients maintained on total parenteral nutrition. While many clinicians prefer to use absolute concentrations to monitor a patient's fatty acid status, reference ranges are not available. Previous reference range studies reported values in terms of percentages only and calculated ranges parametrically. However, due to the non‐Gaussian distributions of some serum fatty acids, it is necessary to calculate reference ranges non‐parametrically. Serum from blood donors (n = 130) were collected and analyzed for total fatty acids by gas‐liquid chromatography. Results for each of the fatty acids were calculated both as a concentration and as a percentage of the total fatty acids measured. © 1994 Wiley‐Liss, Inc.