bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface (Local) Coils as NMR Receivers
Authors: J. H. Ackerman Joseph
Published: March 2007

The advent of “wide bore,” high‐field, high‐homogeneity magnets in the 1970s provided the opportunity to use nuclear magnetic resonance spectroscopy for nondestructive chemical analysis of intact biological systems. Surface or local coils, when used as NMR receivers, provide the NMR experiment with both high signal‐to‐noise sensitivity and a good degree of spatial discrimination. Such attributes are critical to the examination of biological processes in laboratory animals and human patients when concentrations of the metabolites of interest are low and when the sample is characterized by large‐scale heterogeneity, i.e., there are different tissues and organs of interest. The high signal sensitivity also provides for very high spatial resolution when such receivers are used in magnetic resonance imaging of regions such as the spine. This article describes the basic principles of surface coil NMR with the aim of illuminating the concepts underlying its widespread application for in vivo systems.
Phase‐Sensitive Detection. Part I: Phase, Gates, Phase‐Sensitive Detectors, Mixers, and the Rotating Frame
Authors: D. Traficante Daniel
Published: March 2007

The fundamental principles of phase, semiconductor materials, and transformers are presented. The use of diodes and transformers in the construction and operation of product detectors is then described. It is shown that the output of a phase‐sensitive detector “PSD” is a direct‐current “d‐c” voltage when the two inputs have the same frequency, and that the polarity of this voltage depends on the phase difference between the inputs. It is also shown that when the two input frequencies are different, the same device can act as a non‐linear mixer, because its output consists of the difference and the sum of the input frequencies. In an NMR spectrometer, a PSD acts as the heart of the receiver. One of its inputs is the NMR signal from the probe, and the other is a reference frequency obtained from the transmitter. The filtered PSD output is the difference between the two input frequencies, and is referred to as the free induction decay, or FID. It is shown that the reference to the PSD is conceptually analogous to the “rotating frame”. Finally, it is explained that the basic limitation of a single PSD is its inability to determine whether an NMR signal is of a higher or lower frequency than the reference.
A fuzzy PIC multiuser detection/vector channel estimation scheme in Rayleigh fading channels
Authors: Tseng Shu‐Ming
Published: March 2007

We propose a fuzzy parallel interference cancellation (PIC) multiuser detection/vector channel estimation (VCE) scheme in Rayleigh fading channels. The VCE is based on a first‐order auto‐regressive model and an expectation‐maximization algorithm. The signal‐to‐interference ratio and signal‐to‐noise ratio are estimated from the vector channel model's parameters, and we adapt the weight of each interference cancellation pathviafuzzy inference mechanism. The proposed fuzzy PIC and VCE cooperate in a way such that some of the fuzzy PIC input parameters come from the channel predictor and the fuzzy PIC makes the channel predictor be more accurate at the next PIC stage. Computing weightsviafuzzy adaptive method adds insignificant complexity because it involves only table lookup. The simulation results show that the proposed fuzzy PIC/VCE scheme performs better than theimprovedPIC/vector channel estimation scheme with optimal parameter in fast‐varying Rayleigh fading channels. Copyright © 2007 John Wiley & Sons, Ltd.
Range‐Doppler imaging
Authors: Feig Ephraim
Published: March 2007

We review various narrow‐band range‐Doppler imaging methods that have been proposed for radar and highlight the difficulties in their implementation and their limitations. We also present two new imaging schemes. The first involves the transmission of multiplexed chirps, and the second involves simple frequency division multiplexing. The second approach seems to yield the most promising range‐Doppler imaging methods.
SQUID tomographic neuromagnetic imaging
Authors: Singh Manbir , Brechner R. Ricardo
Published: March 2007

The human brain emits a measurable magnetic field in response to stimulation. The aim of neuromagnetic imaging is to produce maps of the underlying neuronal activity from measurements of the emitted magnetic field. Modeling neuronal activity by dipolar current sources, we have previously reported simulation studies to reconstruct planar source distributions using the algebraic reconstruction technique, with the constraint that the sources could only have two orientations. We now present a general solution for two‐dimensionally distributed sources, which is based on measuring both the normal and tangential components of the magnetic field. Also, using a single‐channel SQUID neuromagnetometer, we present results of a tomographic imaging experiment conducted with wires carrying currents to demonstrate the potential of neuromagnetic imaging in reconstructing extended cortical sources.
Low‐level bayesian segmentation of piecewise‐homogeneous noisy and textured images
Authors: Gimel'farb G. L. , Zalesny A. V.
Published: March 2007

We present a novel approach to image segmentation, differing from the known “simulated annealing” method in the following ways: the compound Bayesian decision rule and consequent maximal marginala posterioriprobability (MMAP) estimates of desired region labels in pixels; the two‐ or three‐level piecewise‐homogeneous Gibbs random field with constant control parameters as the probabilistic model of the images and region maps (in the general case such a model integrates the submodels of the region map, of the ideal intensities within each region, and of the noise distorting the ideal intensities); the stochastic relaxation with the constant control parameters of the Gibbs probability distribution only as a tool to obtain the samples of this field and estimate the unknown marginala posterioriprobabilities of the region labels by collecting in each pixel the histogram of labels for these samples; the like stochastic relaxation with directed variation of the control parameters of the Gibbs probability distribution as a tool to find maximal likelihood estimates of the unknown these parameters. Some experimental results are presented.
Fast geometric transformations for image processing
Authors: Musin Oleg R.
Published: March 2007

The algorithms of affine, bilinear, projective, polynomial, and piecewise polynomial transformations of the raster image are suggested. Application of various iterative procedures allows us to reduce considerably the execution time of these transformations in comparison with the programs by the straightforward formulas application.
Experimental comparison of fourier transformation and model‐fitting methods of spectral analysis
Authors: Gardner William A.
Published: March 2007

A summary of the results of an extensive comparative experimental study of Fourier transformation and model‐fitting methods of spectral analysis of random time‐series data is presented. It is illustrated that Fourier transformation methods can be an essential companion to model‐fitting methods even for short data segments with underlying sharp spectral peaks. The best spectrum estimates can be obtained by taking advantage of the strengths of both types of methods. For example, it is shown that detection and estimation of the frequencies of spectral lines for short data segments can be best accomplished using certain parametric methods in conjunction with Fourier transformation methods to aid in model‐order selection and identification of spurious peaks in the parametric spectrum estimate, and that estimation of amplitude and phase for sine‐wave removal, given frequency estimates, and spectrum estimation after sine‐wave removal can often be best accomplished with Fourier transformation methods alone.
Radar imaging
Authors: Mensa Dean L.
Published: March 2007

Radar systems combining coherent signals with frequency and angular diversity offer the possibility of synthesizing images of complex objects with spatial resolution of a few wavelengths. The availability of high‐quality microwave sources and components, high‐speed digital computers, and efficient signal‐processing algorithms allows radar imaging to be implemented in laboratory environments using commercially‐available equipment. The paper summarizes fundamental issues by addressing conceptual and practical limits of radar imaging and presents examples obtained from results of measurements in a laboratory environment. Implementation details of sophisticated operational imaging radars are not covered.©1993 John Wiley & Sons Inc
Digital electro‐optical imaging sensors
Authors: Schueler Carl , Woody Loren
Published: March 2007

A key source of digital images is the electro‐optical imaging sensor. The basic characteristic that identifies a digital electro‐optical sensor is conversion of reflected or emitted light from a scene or object into a digital image signal. Examples include television cameras with digital output, and scanning or staring cameras with digital output. We describe general system design techniques to derive optimum imaging sensor specifications, and we offer examples for two applications. One example application is for terrestrial thermal imaging of nearby objects, such as vehicles. The other example is a sensor to create a color image of small targets in low‐light, such as an automobile license plate from a distance of several meters.©1993 John Wiley & Sons Inc
The residual error of the reflectivity displacement method of SAR motion extraction
Authors: Moreira João R.
Published: March 2007

Reported herein is the estimation of the residual error of the reflectivity displacement method (RDM) and the dependence of RDM on terrain characteristics. The RDM is a method to be implemented on airborne synthetic aperture radars (SAR). It extracts the motion of the aircraft from the radar backscatter signal, allowing for motion compensation without using an inertial navigation system. An extended error analysis of this method and its dependence on the terrain type and contrast is performed. Results proving the estimated performance are shown.
On waveform design for optimal target discrimination
Authors: Riggs Lloyd S. , Richards Michael A. , Shumpert Thomas H. , Smith C. Ray
Published: March 2007

Probability theory is applied to the problem of radar target discrimination. The theory is used to construct an excitation waveform (an enhanced discrimination pulse) which maximizes the posterior odds in favor of one target over the other. It is shown that the enhanced discrimination pulse has its spectrum concentrated near the frequency where the difference in the impulse spectrum of the two targets reaches a maximum. Enhanced discrimination pulses are calculated using analytical models of thin cylindrical targets and experimental data collected from simplified aircraft models.©1993 John Wiley & Sons Inc
Multifrequency backscattering tomography for constant and vertically varying backgrounds
Authors: Wu Ru‐Shan , Araújo Fernanda Vieira , Huang Lian‐Jie
Published: March 2007

To improve the resolution and image quality of the SFDT (Sigle‐Frequency Diffraction Tomography), a special fast multi‐frequency imaging method: Multi‐Frequency Backscattering Tomography (MFBT) is introduced in this paper. The method uses only the backscattered waves (after plane wave decomposition) while maintaining the merit of multi‐frequency method. The method is formulated for both the constant and vertically varying backgrounds. For the latter case the WKBJ approximation is used for the background Green's function. Formulas are derived both for volume scattering using the Born approximation and for boundary scattering using the physical optics approximation. Two reconstruction methods are presented. The backpropagation method can be used and has the same computation speed for both the constant and vertically varying backgrounds. Meanwhile the direct FT method is only formulated for the constant background, in which the backpropagation in z‐direction is implemented by FFT and therefore the computation speed is significantly increased. Compared with the SFDT using backpropagation reconstruction, the MFBT is nearlyNz/log2Nzfaster, whereNzis the number of grid points in z‐direction, and at the same time has a much better resolution and image quality. WhenNzis big, the time saving is remarkable. Compared with other multi‐frequency methods such as the multi‐frequency holography (prestack migration), the speeding factor becomesNfNz/log2Nz, whereNf, is the number of frequencies used. Numerical simulations for both constant and vertically varying backgrounds are performed to demonstrate the feasibility of the method and the quality of reconstructed images for different situations. Examples are also given to show that when the reconstruction procedure of constant background is applied to the case of vertically varying background, the image quality will be greatly deteriorated.©1994 John Wiley & Sons Inc
Orthogonal decomposition framework for ionospheric tomography algorithms
Authors: Sutton Eric , Na Helen
Published: March 2007

Computerized ionospheric tomography (CIT) is one of the most recent developments in the area of remote sensing of the ionosphere. This system is a special case of limited angle tomography in which not only are projection angles limited, but the number of samples per projection varies. This article presents an orthogonal decomposition framework for unifying CIT algorithms including both generalized classical algorithms such as the algebraic reconstruction technique, the direct Fourier method, and filtered backprojection, and algorithms using basis functions from a priori information. This article discusses the orthogonality of the basis functions associated with the classical techniques and presents simulations comparing the use of a priori information in filtered backprojection and orthogonal decomposition.©1994 John Wiley & Sons Inc
Differential and semidifferential invariant signature functions for space curve recognition
Authors: Holt Robert J. , Netravali Arun N.
Published: March 2007

A space curve distorted by certain transformations may be recognized if an invariant description of it is available. Recent research in this area, primarily dealing with plane curves, has shown that it is possible to identify transformed curves through the use of various combinations of differential invariants and point correspondences. Purely differential invariants usually require very high order derivatives of the space curves. However, taking advantage of point correspondences sharply reduces the order of derivatives necessary, especially when the correspondences are between points on the curves. In this case, invariant signature functions requiring the computation of just first‐order derivatives can be constructed with one point correspondence for similarity transformations and two point correspondences for affine transformations. Determining the equivalence of objects reduces to partial function matching when a suitable invariant is known. A detailed example is provided to illustrate our results.©1994 John Wiley & Sons Inc
Some early radiotherapy optimization work
Authors: Cormack A. M.
Published: March 2007

This article presents personal view of an approach to the radiotherapy optimization problem using techniques of classical analysis. This, together with its limitations, can be seen in a broader context in the recent review by Brahme [3].
An intuitive guide to the T1 based perfusion model
Authors: Chesler David A. , Kwong Kenneth K.
Published: March 2007

We explored a number of theoretical and practical approaches used to understand and optimize contrast to noise of the versatile T1 based perfusion model. The interplay between tissue T1 and blood T1 was investigated. We also provided a succinct evaluation of the several popular T1 based methods currently applied to measure flow and flow change.
Pixon‐based multiresolution image reconstruction and the quantification of picture information content
Authors: Puetter R. C.
Published: March 2007

This article reviews pixon‐based image reconstruction, which in its current formulation uses a multiresolution language to quantify an image's algorithmic information content (AIC) using Bayesian techniques. Each pixon (or its generalization, theinformation) represents a fundamental quanta of an image's AIC, and an image's pixon basis represents the minimum degrees of freedom necessary to describe the image within the accuracy of the noise. We demonstrate with a number of examples that pixon‐based image reconstruction yields results consistently superior to popular competing methods, including maximum likelihood and maximum entropy methods. Typical improvements include higher spatial resolution, greater sensitivity to faint sources, and immunity to the production of spurious sources and signal correlated residuals. Finally, we show how the pixon provides a generalization of the Akaike information criterion, and how it relates to concepts of “coarse graining” and the role of the Heisenberg uncertainly principle in statistical mechanics, provides a mechanism for optimal data compression, and represents a more optimal basis for image compression or reconstruction than wavelets.
The catalytically inactive precursor of cathepsin D induces apoptosis in human fibroblasts and HeLa cells
Authors: Schestkowa Olga , Geisel Dominik , Jacob Ralf , Hasilik Andrej
Published: March 2007

In several reports cathepsin D has been implicated in apoptosis. In some systems the effects of agents considered to be mediated by cathepsin D were inhibited in the presence of pepstatin A, an inhibitor of the enzyme. In other studies the effect of a mutant cathepsin D deprived of activity was indistinguishable from that of the normal enzyme. Here we show that in human fibroblasts and in HeLa cells apoptosis can be induced by microinjecting into cytosol either mature cathepsin D or its inactive precursor procathepsin D. The microinjected precursor remains in the uncleaved form. These results confirm that the proapoptotic effect of cathepsin D in the cytosol is independent of its catalytic activity and suggest that the interaction of cathepsin D with the downstream effector does not involve the active site of the enzyme, since in the proenzyme the active site is masked by the prosequence. J. Cell. Biochem. J. Cell. Biochem. 101: 1558–1566, 2007. © 2007 Wiley‐Liss, Inc.
The DNA topoisomerase IIβ binding protein 1 (TopBP1) interacts with poly (ADP‐ribose) polymerase (PARP‐1)
Authors: Wollmann Yvonne , Schmidt Uta , Wieland Gerhard D. , Zipfel Peter F. , Saluz Hans‐Peter , Hänel Frank
Published: March 2007

We investigated the physical association of the DNA topoisomerase IIβ binding protein 1 (TopBP1), involved in DNA replication and repair but also in regulation of apoptosis, with poly(ADP‐ribose) polymerase‐1 (PARP‐1). This enzyme plays a crucial role in DNA repair and interacts with many DNA replication/repair factors. It was shown that the sixth BRCA1 C‐terminal (BRCT) domain of TopBP1 interacts with a protein fragment of PARP‐1 in vitro containing the DNA‐binding and the automodification domains. More significantly, the in vivo interaction of endogenous TopBP1 and PARP‐1 proteins could be shown in HeLa‐S3 cells by co‐immunoprecipitation. TopBP1 and PARP‐1 are localized within overlapping regions in the nucleus of HeLa‐S3 cells as shown by immunofluorescence. Exposure to UVB light slightly enhanced the interaction between both proteins. Furthermore, TopBP1 was detected in nuclear regions where poly(ADP‐ribose) (PAR) synthesis takes place and is ADP‐ribosylated by PARP‐1. Finally, cellular (ADP‐ribosyl)ating activity impairs binding of TopBP1 to Myc‐interacting zinc finger protein‐1 (Miz‐1). The results indicate an influence of post‐translational modifications of TopBP1 on its function during DNA repair. J. Cell. Biochem. 102: 171–182, 2007. © 2007 Wiley‐Liss, Inc.
Comparison of the numerical stability of methods for anharmonic calculations of vibrational molecular energies
Authors: Daněček Petr , Bouř Petr
Published: March 2007

On model examples, we compare the performance of the vibrational self‐consistent field, variational, and four perturbational schemes used for computations of vibrational energies of semi‐rigid molecules, with emphasis on the numerical stability. Although the accuracy of the energies is primarily dependent on the quality of the potential energy surface, approximate approaches to the anharmonic vibrational problem often do not converge to the same results due to the approximations involved. For furan, the sensitivity to variations of the anharmonic potential was systematically investigated by adding random noise to the cubic and quartic constants. The self‐consistent field methods proved to be the most resistant to the potential variations. The second order perturbational techniques are sensitive to random degeneracies and provided the least stable results. However, their stability could be significantly improved by a simple generalization of the perturbational formula. The variational configuration interaction is practically limited by the size of the matrix that can be diagonalized for larger molecules; however, relatively fewer states need to be involved than for smaller ones, in favor of the computing. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Enzyme immunoassay for c‐reactive protein analysis
Authors: Unten Sharon K. , Hokama Y.
Published: March 2007

A solid‐phase enzyme immunoassay method using goat anti‐CRP sensitized to polyvinyl 96 well plates and a second rabbit anti‐CRP highly specific for gamma mobility CRP is described in this study. Examination of serum samples of normal healthy individuals from cord blood, children (2–12 yr) and adults (16–83 yr) by this EIA method showed a progressive increase in CRP levels with age. The mean and standard error of the mean in ng/ml CRP was as follows with respect to age distribution: cord blood, 310 ± 54; children (2–12 yr), 664 ± 87; adults (16–35 yr), 1,145 ± 116; adults (36–50 yr), 3,775 ± 605; and adults (51–83 yr), 7,718 ± 1,482. Individuals in the age range of 22–34 yr with one or more abnormality in the chemistry profile analysis showed CRP levels with a higher X ± S.E.M. (3,615 ± 925). This is in contrast to the normal individuals of the same age range (1,145 ± 116). This EIA method is sensitive, reproducible, and specific. It should be a useful quantitative method for monitoring low level CRP responders, such as newborn and cord blood serum.
Occult leukocyte and tumor‐associated antigens assessed by flow cytometry: A Review
Authors: Morgan Alton C. , Schroff Robert W. , Ortaldo John R. , Herberman Ronald B.
Published: March 2007

We have developed a method for assessing the reactivity of monoclonal antibodies with intracellular antigens. This procedure has been utilized to evaluate the reliability of leukocyte surface antigens as markers of lymphoid cell lineages and for leukemic cell classification, and to further examine the specificity of tumor‐associated antigens. Occult expression of certain leukocyte antigens was found in human large granular lymphocytes (LGL), the cells responsible for natural killer (NK) activity. These included the T65 antigen, a T‐cell‐associated antigen recognized by monoclonal antibodies T101 and Leu‐1; the 140Kd 6–cell‐associated glycoprotein recognized by monoclonal antibody 82; and the molecules recognized by the monocytel macrophage antibody MO‐2. Thus, T‐cell, B‐cell, and monocyte markers were detected intracellularly in human LGL but not on the surface. Similarly, normal T‐cells expressed the 6‐2 and MO‐2 markers intracellularly. The pan‐T‐cell antigen Leu‐4 (OKT‐3) was found to be expressed intracellularly in normal monocytes and in B‐cell chronic lymphocytic leukemia cells. In addition, a secreted 100Kd human melanoma‐associated antigen as well as vH‐ras‐p21 oncogene product could be demonstrated intracellularly in high amounts in human tumor and viral‐transformed cells. These results indicate that leukocyte differentiation and tumor‐associated antigens are expressed in a wider variety of cells than previously detected on the cell surface; and therefore cell lineage and specificity studies require a reassessment.
Serum pregnancy‐associated α2‐glycoprotein levels in the evolution of Hepatitis B virus infection
Authors: Zarzur Jorge A. , Aldao Mario , Sileoni Santos , Vides Miguel A.
Published: March 2007

Serum pregnancy‐associated α2‐glyco‐protein (α2‐PAG) levels were evaluated in a follow‐up study of patients with hepatitis B virus (HBV) infection and compared with biochemical and virological parameters. In a study of 25 patients with acute hepatitis, an association was found between high a2‐PAG values, ALT levels, and HBsAg in 20 patients (80%) (P<0.05), 18 recovered completely, and 2 had a protracted course. In five patients serum a2‐PAG levels were similar to those in the control group. On the other hand, eight (100%) chronic persistent HEW patients showed high levels of α2‐PAG (P < 0.05) during the study period, and these levels correlated well with inflammatory activity and failure of HBsAg elimination. There were no significant differences in α2‐PAG values between asymptomatic HBsAg carriers and controls.

Serial analysis of α2‐PAG, in correlation with viral markers, biochemical parameters, and histological data, would contribute to the ability to predict the final outcome of HBV infection.
Detection of the ras p21 gene product in human leukemias by flow cytometry
Authors: Takeda Tetsuo , Krause John R. , Carey John L. , McCoy J. Philip
Published: March 2007

To date, the detection of oncogene products in human neoplasms has relied primarily upon immunoblot analysis of specimen homogenates. Herein are reported the results of a study using flow cytometry to evaluate the expression of the ras p21 gene product in both fresh and cryopreserved specimens of human acute leukemias. Cell lines known to express ras p21 were used as positive controls and normal peripheral blood was used as a negative control. Intensity of staining for ras p21 (lp21) was expressed as the ratio of the peak channel numbers of the peak generated by staining with anti‐ras p21 to the peak obtained by staining with an isotype control. Using this method, 21 out of 32 clinical specimens of acute leukemia were found to express ras p21 in elevated amounts compared to normal peripheral blood. Flow cytometry appears to be a practical method for routine screening of clinical specimens for the expression of oncogene products on individual cells rather than cell homogenates.
Diagnostic value of ganglioside patterns in plasma of human diseases
Authors: Ayabe M. , Shichijo S. , Yokoyama M. M.
Published: March 2007

A method that could be facilitated for the quantitation and qualitation of gangliosides in human plasma was developed and applied in the present study for characterization of ganglioside patterns in plasmas of patients with neoplastic diseases including gastric cancer, adult T‐cell leukemia (ATL), and acute lymphocytic leukemia (ALL). As a retrovirus‐infected disease with different clinical entity, human T‐cell lymphotropic virus type I‐associated myelopathy (HAM) was also subjected to this study. The results were compared with the patterns obtained from normal control plasmas. The analytical data revealed that GM3 increased in gastric cancer, GT1 b decreased in HAM and ATL, and GD3, GM1 and GM3 decreased in ALL. There were close correlations between various human diseases and the presence of gangliosides with their specific patterns. Furthermore, gangliosides purified from plasma of patients with HAM significantly inhibited the expression of CD4 antigen on human T lymphocyte membrane. Therefore, analytical studies of plasma gangliosides could provide diagnostic and therapeutic values in retroviral infections.
Clinical applications of luminescent assays for enzymes and enzyme labels
Authors: Bronstein Irena , Kricka Larry J.
Published: March 2007

A wide range of luminescent assays for enzyme labels has been developed. The clinical application of luminescent assays for horseradish peroxidase, alkaline phosphatase, xanthine oxidase, beta‐D galactosidase, and glucose 6‐phosphate dehydrogenase is discussed. The enzyme luminescent methods provide improved sensitivity compared with colorimetric and fluorimetric assays. A new reagent, dioxetane phosphate, has provided a simple and extremely sensitive assay for alkaline phosphatase. The available instruments and new photographic detection techniques for luminescent assays are briefly discussed.
Cerebrospinal fluid corticotropin‐releasing factor levels and stimulation test in dementia of the alzheimer type
Authors: Martignoni Emilia , Costa Alfredo , Nappi Giuseppe , Petraglia Felice , Monzani Anna , Genazzani Andrea R.
Published: March 2007

Experimental findings have recently suggested a toxic role for glucocorticoids in hippocampus, the main brain target for the adrenocortical hormones. In this study, we explored the activity of the hypothalamus‐pituitary‐adrenal (HPA) axis in a group of patients with dementia of the Alzheimer's type (DAT) and in a control group of age‐matched subjects. We measured the corticotropin‐releasing factor (CRF) levels in cerebrospinal fluid (CSF) and evaluated the plasma cortisol response to a CRF stimulation test. While no differences were observed in the results of the CRF test for two groups, CSF CRF values in DAT patients were found to be significantly higher than in controls. Bearing in mind the bidirectional relationships between the neuroendocrine and immune systems and the changes in some immunological parameters reported in DAT, the possible role of HPA axis hyperactivity in the pathogenesis of primary dementia is discussed.
Failure of orthoclone okt3 retreatment in a pancreas transplant recipient with antimurine antibodies
Authors: Schroeder Timothy J. , Hurtubise Paul E. , Munda Rino , Pedersen Susan H. , Wesley Alexander J. , Roy First M.
Published: March 2007

Orthoclone OKT3 is a murine monoclonal antibody that blocks the generation and function of T lymphocytes. It has been shown to be effective in reversing acute cellular rejection in solid organ transplants. However, potential development of antimurine antibodies restricts the duration that the drug can be used and the ability to reuse the drug. The case reported in this article illustrates the failure of retreatment with OKT3 when high titer (1:3200) antimurine antibodies are present. Lack of efficacy of the drug was documented by virtually undetectable circulating OKT3 levels in plasma, no decrease in T3 lymphocytes, and organ rejection. OKT3 should only be reused when immune monitoring (antimurine antibody status, lymphocyte subsets, and OKT3 plasma levels) is performed before, during, and after its use. Patients with high‐titer anti‐OKT3 antibody should not be retreated with OKT3.
Evaluation of the Beckman Synchron cx4 clinical chemistry analyzer in a hospital laboratory
Authors: Ambus T. , Korogyi N. , Decampos F. , Groom B. , Innanen V. T.
Published: March 2007

The Beckman Synchron CX4 random‐access multianalyzer was evaluated in a medium sized hospital laboratory. The instrument does end‐point, rate, and multipoint assays and carries on‐board reagents for 24 tests. In addition to predefined tests, the instrument can be programmed for 100 user‐defined tests; these are stored on the hard disk and can utilize up to three component reagents each. The throughput is 200 tests per hour. There is stat testing capability. In our evaluation, within‐run and between‐run precision and linearity were good, and no reagent carryover was detected. There was good correlation with the in‐house methodology for the 19 tests evaluated. A disadvantage at the time of evaluation was interference by elevated bilirubin on creatinine, phosphorus, uric acid, and triglycerides. This problem of interference is being addressed by the manufacturer.
Lack of leu‐3a epitope on t‐helper (cd4) lymphocytes
Authors: Angadi Channabasappa V.
Published: March 2007

Human T‐helper cells express membrane‐bound CD4 antigen whose many epitopes are recognized by different monoclonal antibodies. The epitope recognized by Leu‐3a and similar clones has been shown to be the location for human immunodeficiency virus (HIV) receptor. We have found a unique blood donor whose CD4+ T‐helper lymphocytes were lacking Leu‐3a epitope. CD4+ T‐helper cells lacking Leu‐3a epitope might be resistant to HIV infection.
Novel and sensitive enzyme immunoassay (immune‐complex‐transfer enzyme immunoassay) for antihuman t cell leukemia virus type 1 igg in human serum using recombinant gag‐env hybrid protein as antigen
Authors: Kohno Hiroaki , Kohno Takeyuki , Ishikawa Eiji , Sakoda Iwane
Published: March 2007

A novel and sensitive enzyme immunoassay (immune‐complex‐transfer enzyme immunoassay) for antihuman T cell leukemia virus type 1IgG (anti‐HTLV‐1 IgG) in human serum using recombinant gag(14‐139)‐env‐(197‐295) hybrid protein is described. Anti‐HTLV‐1 IgG in test serum was reacted with dinitrophenyl biotinyl bovine serum albumin‐recombinant gag‐env hybrid protein conjugate. The complex formed was trapped onto polystyrene balls coated with affinity‐purified antidinitrophenyl group IgG. After washing to eliminate nonspecific IgG in the test serum, the complex was eluted from the polystyrene balls with dinitrophenyl‐L‐lysine and transferred to polystyrene balls coated with streptavidin. After washing, anti‐HTLV‐1 IgG in the complex trapped onto the streptavidin‐coated polystyrene balls was reacted with antihuman IgG γ‐chain Fab′‐peroxidase conjugate. Peroxidase activity bound to the streptavidin‐coated polystyrene balls was assayed by fluorometry. By transfer of the complex, the nonspecific binding of nonspecific human IgG was considerably reduced, and the detection limit of anti‐HTLV‐1 IgG in serum was lowered 30‐300‐fold compared with that by Western blotting, gelatin particle agglutination, and the conventional enzyme immunoassay, in which a recombinant gag‐env hybrid protein‐coated polystyrene ball was incubated with test serum and, after washing, with antihuman IgG γ‐chain Fab′‐peroxidase conjugate. Usefulness of the immune‐complex‐transfer enzyme immunoassay was demonstrated using 271 serum samples.
Angiotoxicity and atherogenicity of cholesterol oxides
Authors: Peng Shi‐Kaung , Hu Bin , Morin Robert J.
Published: March 2007

Cholesterol in the diet can readily autoxidize and be absorbed and transported in plasma lipoproteins. Cholesterol oxides can also be endogenously produced in tissues via free‐radical‐induced reactions. Some cholesterol oxides, notably cholestane‐3β,5α,6β‐triol and 25‐hydroxycholesterol, have been shown to cause injury to vascular endothelial and smooth muscle cells, to alter LDL receptor function, to enhance cholesteryl ester accumulation, to inhibit prostacyclin production, and to induce experimental atherosclerosis alone or in combination with cholesterol. An epidemiological study examining relationships between atherosclerosis and plasma levels of cholesterol oxides as independent risk factors may provide additional insights regarding the roles of cholesterol oxides in atherogenesis.
Prenatal sexing and detection of zfy gene sequences in sex chromosome disorders by polymerase chain reaction
Authors: Sasi R. , Fan Y.‐S. , Lin C. C.
Published: March 2007

Specific amplification of a DNA segment of the human ZFY gene by polymerase chain reaction (PCR) was carried out for detection of Y‐chromosome specific sequences. When male DNA was used as template for amplification, a single and discrete 530 bp ethidium bromide staining band was observed in agarose gel. Female DNA produced no band. This technique was successfully used in prenatal sexing and for detecting ZFY DNA sequences in five XX males, an XY female, and a female patient with Turner syndrome having mosaicism involving a minute marker chromosome.
Selection criteria for liver transplant donors
Authors: Schroeder Timothy J. , Pesce Amadeo J. , Ryckman Frederick C. , Tressler Thomas P. , Brunson Matthew E. , Tchervenkov Jean I. , Penn Israel , Alexander J. Wesley , Pedersen Susan H. , Balistreri William F.
Published: March 2007

As the number of successful liver transplants has increased, the demand for donors has outpaced the supply. Approximately 25% of patients die awaiting an appropriate donor. Current criteria for assessing potential donors need to be closely examined. Fifty‐six potential donors were evaluated by our transplant team by utilizing standard liver function tests (LFT's)—SGOT, SGPT, bilirubin. Additionally, a lidocaine metabolism test was performed by giving a 1 mg/kg IV dose of lidocaine over 1 minute and measuring the accumulation of the major metabolite monoethylglycinxylidide (MEGX) at 15 minutes by fluorescent polarization immunoassay (Abbott Diagnostics, Abbott Park, IL). Previous work has suggested that a MEGX <50 ng/mL is associated with initial non‐function. Thirty‐four donors were transplanted (group l) and all had initial function (all MEGX values were >50). Twenty‐two donors (39%) were judged unacceptable (group II) by our transplant team and by outside centers based upon one of the following criteria: II (A) elevated LFT's—8, II (B) donor age—5, II (C) donor instability—4, II (D) no available recipient—3, II (E) miscellaneous—2. Standard LFT's were not statistically different in the donors used and in those not used when excluding category II A. Six of seven donors excluded in group I had acceptable MEGX values indicating they may have been transplantable. Ten of 12 patients excluded in groups II B–D had normal LFT's and nine of 12 had acceptable MEGX values indicating they may have been transplantable also. In this era of organ shortage, a reevaluation of donor selection criteria utilizing new tests like MEGX may be necessary to meet the increased need.
Simple elisa method for the evaluation of soluble hla class i antigens in human serum
Authors: Comuzio Sergio , Orlandini Alessandro , Grillo Franco , Puppo Francesco , Ruzzenenti Rosaria , Brenci Sabrina , Lanza Lorella , Scudeletti Marco , Indiveri Francesco
Published: March 2007

A simple sandwich ELISA method has been developed for the quantification of souble HLA class I antigens (s‐HLA) in human serum. The assay utilizes the monoclonal antibody Q6/64, directed to a monomorphic determinant of the HLA α‐chain, to capture the antigen and the biotinylated NAMB1 monoclonal antibody, directed to β2‐microglobulin, as the detection antibody. The extract of the LG‐2 lymphoid cell line and pooled sera from 100 healthy subjects are utilized as standards. The arbitrary value of 100 s‐HLA Relative Units/mL (RU/mL) is given to the 1:20 dilution of pooled human sera whose optical density value corresponds to the one of the extract of 1 × 106 LG‐2 cells (6.25 μg/mL protein concentration). The assay is easy to perform, specific, reproducible (intra‐and inter‐assay variations ranging from 3.2% to 8.87%), sensitive (detection limit of 6 RU/mL), and needs a small amount of serum (0.1 mL), The mean serum levels of s‐HLA found in 100 healthy normal subjects are 41.9 ± 13.4 RU/mL. The potential uses of the method are discussed.
Evaluation of four commercially available elisa assays for the serologic diagnosis of lyme disease
Authors: Christenson Vicki D. , White Diane H.
Published: March 2007

We evaluated four commercially available ELISAs for detection of antibody to Borrelia burgdorferi with 21 sera from patients with clinically diagnosed Lyme disease and 89 patient control sera. Patient control sera included 28 sera from patients with rheumatoid arthritis (RA), 17 sera from patients with systemic lupus erythematosus (SLE), and 44 sera containing antibodies reported to crossreact in some Lyme disease tests. The ELISAs tested (Cambridge Bioscience, Diamedix, 3M, and Zeus) detect antibodies (IgM and/or IgG) that bind Borrelia burgdorferi antigen attached to microtiter wells. Antibody reactivity in the sera from patients with clinically diagnosed Lyme disease was characterized by using Zeus immunoglobulin class‐specific assays (IgM and IgG). Sensitivities in early and late Lyme disease were as follows: Cambridge and Diamedix, 57% and 100%; 3M, 57% and 93%; and Zeus, 71% and 86%. Reactivities within a patient control population were: Cambridge and Diamedix, 3%; 3M, 7%; and Zeus, 10%.
Carcinoembryonic antigen gene family: Molecular biology and clinical perspectives
Authors: Thompson John A. , Grunert Fritz , Zimmermann Wolfgang
Published: March 2007

The carcinoembryonic antigen (CEA) gene family belongs to the immunoglobulin supergene family and can be divided into two main subgroups based on sequence comparisons. In humans it is clustered on the long arm of chromosome 19 and consists of approximately 20 genes. The CEA subgroup genes code for CEA and its classical crossreacting antigens, which are mainly membrane‐bound, whereas the other subgroup genes encode the pregnancy‐specific glycoproteins (PSG), which are secreted. Splice variants of individual genes and differential post‐translational modifications of the resulting proteins, e.g., by glycosylation, indicate a high complexity in the number of putative CEA‐related molecules. So far, only a limited number of CEA‐related antigens in humans have been unequivocally assigned to a specific gene. Rodent CEA‐related genes reveal a high sequence divergence and, in part, a completely different domain organization than the human CEA gene family, making it difficult to determine individual gene counterparts. However, rodent CEA‐related genes can be assigned to human subgroups based on similarity of expression patterns, which is characteristic for the subgroups. Various functions have been determined for members of the CEA subgroup in vitro, including cell adhesion, bacterial binding, an accessory role for collagen binding or ecto‐ATPases activity. Based on all that is known so far on its biology, the clinical outlook for the CEA family has been reassessed.
Specific hla‐dqa and hla‐drb1 alleles confer susceptibility to sjögren's syndrome and autoantibody production
Authors: Fei Hong Ming , Kang Hoil , Peebles Carol , Fox Robert , Scharf Stephen , Erlich Henry
Published: March 2007

Primary Sjögren's syndrome (1° SS) is a systemic autoimmune disease characterized by lymphocytic infiltration of the salivary glands and autoantibody production. In order to identify genetic factors that play a role in pathogenesis and predict extent of disease, we used Southern blot and polymerase chain reaction (PCR) methods to detect polymorphisms of the HLA‐DRB1 (DR), HLA‐DRB3 (DRw52), and HLA‐DQA1 genes among 75 Caucasoid 1° SS patients and 150 Caucasoid controls living in the same geographic region of Southern California. We found significantly increased frequency of HLA‐DR3 (P < .001), HLA‐DW52a (P < .001), and HLA‐DQA4 (P < .05), in comparison to normal controls. Also, an increased frequency of heterozygosity for HLA‐DQA1/DQA4(P < .05) was present among 1° SS patients. Autoantibodies to SS‐A and to SS‐B were significantly associated with DR3 (P < .001), HLA‐DQA4, (P < .05), and DQA4/DQA1 heterozygotes (P < .01). Among the 1° SS patients, clinical and laboratory features such as hypergammaglobulinemia, symmetric peripheral neuropathy, and hypothyroidism were significantly associated with HLA‐DR3 (P < .01) but not with HLA‐DR2 (P > .10). In comparison, 1° SS patients with leukocytoclastic vasculitis were more frequently HLA‐DR2 (P < .05). These results using PCR methods confirm and extend prior studies that have used serologic methods.
A new sensitive microplate assay of plasma endotoxin
Authors: Tamura Hiroshi , Tanaka Shigenori , Obayashi Taminori , Yoshida Minoru , Kawai Tadashi
Published: March 2007

We have developed a microplate method for determining endotoxin in platelet‐rich plasma‐using Endospecy, an endotoxinspecific chromogenic Limulus test reagent. Nonspecific activators and inhibitors of the test were eliminated by exposing samples (5μl) to the alkali reagent consisting of KOH, CaCl2, Triton X‐100, ethyleniminepolymer and N,N‐bis(2‐hydroxyethyl)glycine. The recoveries of various endotoxins were almost complete and not enhanced by dilution. The dose—response curve was linear over endotoxin concentrations of 2–400 pg/ml with good precision (C.V.<5.0%). Normal human plasmas (n=30) contained <5.0 pg/ml of endotoxin in reference to that of Escherichia coli 0111:B4. All plasma samples with high concentration of endotoxin by a conventional method showed high values by the microplate assay as well. Since it does not require centrifugation, the new treatment allows the whole reactions to proceed on the same microplate. This permits us to apply the Limulus test to an automated assay system, making plasma endotoxin determination simpler and more rapid than a conventional test tube method. © 1992 Wiley‐Liss, Inc.
Rhabdomyosarcoma cell line can be used for the isolation of soluble acetylcholine receptor and for assaying blocking and modulating autoantibodies
Authors: Wu James T. , Astill Mark , Lloyd Christopher , Salmon V. C.
Published: March 2007

We found that the Rhabdomyosarcoma (RD) cell line expresses human acetylcholine receptor (AChR) based on the following evidences: 1. Soluble AChR can be isolated from RD cells following the isolation procedure for AChR from human muscle; 2. Intact RD cells bind to alpha‐bungarotoxin (αButx) in a time‐dependent and saturable fashion. The apparent dissociation constant (5.3 × 10−10 M) is very similar to that reported for TE671 cells, which is known to express AChR; 3. Like fresh muscle culture, RD cells not only bind but also internalize 125l‐αButx.

Soluble AChR from RD cells can be labeled specifically with 125l‐αButx and then used to quantify binding autoantibodies in myasthenic patients. We also demonstrate that blocking antibodies can be detected in sera from patients with myasthenia gravis (MG) using RD cells and the ability of RD cells to internalize αButx. Consequently, RD cells can be used as a reliable source for obtaining soluble AChR and as a replacement for rodent or human muscle cultures in measuring blocking and modulating antibodies. © 1993 Wiley‐Liss, Inc.
Application of checkerboard immunoblotting (CBIB) to the detection of anti‐viral IgG in human serum
Authors: Craig Wendy Y. , Poulin Sue E. , Dorsett Preston H. , Ledue Thomas B. , Ritchie Robert F.
Published: March 2007

In the present study, we have begun to investigate the possibility of using checkerboard immunoblotting (CBIB) as a semi‐quantitative screening tool for detecting human serum IgG against specific viral antigens. The viral antigens studied were Epstein‐Barr, herpes simplex I and II, cytomegalovirus, varicella zoster, rubella, rubeola, and mumps. Western immunoblotting experiments using these partially purified preparations demonstrated that there were apparently no interactions between IgG from non‐immune sera and the respective viral antigen preparations. The CBIB assay was evaluated using sera of known positive or negative immune status for the viral antigens. There was excellent agreement between the results of CBIB and the results of alternative methods for evaluating immune status; all discrepancies (1/18 sera for mumps, 3/18 sera for rubeola, and 1/28 sera for rubella) involved sera with borderline results, either by CBIB or by the alternative method. Therefore, although further work is required to define the method in terms of sensitivity and clinical specificity, and to refine positive/negative cutpoint criteria for certain antigen components, our preliminary experience suggests that CBIB has considerable potential in the efficient and inexpensive screening of sera for the presence of IgG against a panel of viral antigens, so as to identify subjects at risk for infection. © 1993 Wiley‐Liss, Inc.