bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring Self‐Esteem in Context: The Importance of Stability of Self‐Esteem in Psychological Functioning
Authors: Kernis Michael H.
Published: September 2005

Abstract
In this article, I report on a research program that has focused on the joint roles of stability and level of self‐esteem in various aspects of psychological functioning. Stability of self‐esteem refers to the magnitude of short‐term fluctuations that people experience in their current, contextually based feelings of self‐worth. In contrast, level of self‐esteem refers to representations of people's general, or typical, feelings of self‐worth. A considerable amount of research reveals that self‐esteem stability has predictive value beyond the predictive value of self‐esteem level. Moreover, considering self‐esteem stability provides one way to distinguish fragile from secure forms of high self‐esteem. Results from a number of studies are presented and theoretical implications are discussed.
The effect of combination antiretroviral therapy on CD5 B‐ cells, B‐cell activation and hypergammaglobulinaemia in HIV‐1‐infected patients
Authors: Redgrave BE , Stone SF , French MAH , Krueger R , James IR , Price P
Published: September 2005

Objectives

This study assessed B‐cell activation, CD5 B‐cells and circulating immunoglobulin levels in HIV‐infected patients treated with combination antiretroviral therapy (CART).

Methods

Measurement of plasma immunoglobulin levels and electrophoresis of plasma proteins, and analyses of total numbers of B‐cells and B‐cells expressing CD38 and CD5 in whole blood, were undertaken in 47 consecutive HIV‐1‐infected patients attending an out‐patient clinic.

Results

All HIV‐infected patients had similar percentages and numbers of B‐cells. Proportions of CD5 B‐cells in all HIV‐infected patients were significantly lower than those in HIV‐negative controls. Aviraemic HIV‐infected patients on CART had lower percentages of CD5, CD38 and CD5 CD38 B‐cell subsets and lower plasma levels of immunoglobulin G (IgG) and immunoglobulin A (IgA) than viraemic HIV‐infected patients (untreated or on CART). However, 33–37% of aviraemic HIV‐infected patients had IgG and IgA levels above the 95th percentile of the normal range defined in HIV‐seronegative donors. In aviraemic HIV‐infected patients, plasma IgA levels correlated only with proportions of activated (CD38) B‐cells. IgG levels did not correlate with the proportions of B‐cell subsets or any marker of HIV disease activity. Monoclonal immunoglobulins were not detected in any plasma sample.

Conclusions

Aviraemic HIV‐infected patients on CART have lower plasma levels of IgG and IgA than viraemic HIV‐infected patients, but levels are often above the normal range. CD5 B‐cell numbers are depressed, so these cells are unlikely to contribute to hypergammaglobulinaemia in HIV‐infected patients.
Laser scanning as a tool for assessment of HIV‐related facial lipoatrophy: evaluation of accuracy and reproducibility
Authors: Yang Y , Paton NI
Published: September 2005

Background
Facial lipoatrophy (LA) is a common complication of highly active antiretroviral therapy (HAART). Research into causes and treatment of facial LA is hindered by the lack of an objective measurement tool.

Objective
To evaluate the accuracy and reproducibility of three‐dimensional laser scanning (LS) for estimating cheek volume changes.

Methods
Paired laser scans were performed and the images superimposed using commercial software. The volume difference between images was computed within a circle of radius 25 mm placed in a standardized position over the cheek area. Accuracy was tested by scanning before and after known volumes of plasticine (0.5–5 mL) were applied to the cheek area of a mannequin to simulate volume change. Reproducibility was tested by repeated scanning of the mannequin with and without 2 mL of plasticine, and repeated scanning of 10 healthy subjects over the course of 1 week.

Results
The mean difference between actual and estimated volume change was small across the range of volumes tested [mean difference 0.08 mL; 95% confidence interval (CI)–0.36 to 0.20 mL). The coefficient of variation for repeated measurements of 2‐mL volume change was 5.8%. The intraclass correlation coefficient for scan‐to‐scan variability was 0.812 (95% CI 0.515–0.947) and for day‐to‐day variability it was 0.764 (95% CI 0.332–0.935).

Conclusions
LS is an accurate and reproducible method for estimating cheek volume changes. It may be useful as an objective tool for assessment of facial LA in clinical research studies.
The long‐term pharmacokinetics and safety of adding low‐dose ritonavir to a nelfinavir 1250 mg twice‐daily regimen in HIV‐infected patients
Authors: Justesen US , Hansen IM , Andersen ÅB , Klitgaard NA , Black FT , Gerstoft J , Mathiesen LR , Pedersen C
Published: September 2005

Objectives

To evaluate the long‐term pharmacokinetics and safety of adding ritonavir 100 mg twice‐daily to a nelfinavir 1250 mg twice‐daily regimen in HIV‐infected patients.

Methods

This was a prospective, randomized, open‐label, controlled 24‐week study. Sixteen patients receiving a nelfinavir 1250 mg twice‐daily regimen with plasma viral load <1000 HIV‐1 RNA copies/mL were randomized to continue treatment or to have ritonavir 100 mg twice‐daily added. Safety, including fasting lipid levels, was evaluated at weeks 4, 12 and 24. Patients who were randomized to have ritonavir added (n=9) participated in three 12‐h pharmacokinetic evaluations at baseline, week 4 and week 24.

Results

Increases in median nelfinavir steady‐state plasma concentrations at 12 h (C12) from 512 to 773 ng/mL [median difference 450 ng/mL; 95% confidence interval (CI) 116–1510 ng/mL] and in median active nelfinavir metabolite M8 C12 from 107 to 603 ng/mL (median difference 545 ng/mL; 95% CI 370–891) were seen after the addition of low‐dose ritonavir (baseline to week 24). There were no differences between the nelfinavir or M8 pharmacokinetic parameters at weeks 4 and 24. No significant changes or differences in the concentration of fasting total cholesterol, low‐density lipoprotein (LDL) cholesterol or total triglycerides or in the occurrence of adverse events were observed within or between the two groups.

Conclusions

Nelfinavir and especially M8 concentrations are increased when low‐dose ritonavir is added to a nelfinavir‐containing regimen. The combination seems to be safe and the nelfinavir/ritonavir regimen could be an option in patients with low nelfinavir+M8 concentrations.
The development of hypophosphataemic osteomalacia with myopathy in two patients with HIV infection receiving tenofovir therapy
Authors: Parsonage MJ , Wilkins EGL , Snowden N , Issa BG , Savage MW
Published: September 2005

We report two cases in which osteomalacia developed in patients on tenofovir‐containing highly active antiretroviral therapy (HAART) in the context of Fanconi syndrome with hypophosphataemia. Bone pain was the presenting feature and myopathy followed in one case. Disability was reversed with withdrawal of the drug and with mineral supplementation. The cases highlight the importance of considering the diagnosis of osteomalacia in patients treated with tenofovir. A possible association with incipient acute renal failure, particularly during nonsteroidal anti‐inflammatory drug (NSAID) use, needs further investigation.
A randomized controlled trial investigating the efficacy and safety of switching from a protease inhibitor to nevirapine in patients with undetectable viral load
Authors: Arranz Caso JA , López JC , Santos I , Estrada V , Castilla V , Sanz J , Sanz J , Molina JP , Fernández Guerrero M , Górgolas M
Published: September 2005

Objective

To assess the antiviral efficacy and safety of switching from a protease inhibitor (PI) to nevirapine in patients with long‐term HIV‐1 RNA suppression on PI‐containing regimens, and to assess its influence in the adherence to treatment.

Methods

In an open‐label multicentre study, 160 HIV‐infected patients with undetectable viral load for at least 6 months on a PI‐containing regimen were randomized to either continue with their PI regimen (n=79) or replace PI with nevirapine (n=81). Clinical assessment included plasma HIV‐1 RNA, blood chemistry, haematology, lymphocyte counts and adverse events reports. Adherence to treatment and lipodystrophy syndrome were assessed by patient self‐reporting.

Results

Treatment efficacy was equivalent in the two arms, for patients with viral loads either above or below 100 000 HIV‐1 RNA copies/mL. The increase in CD4 cell count was significant in both arms (P<0.00001) but the average CD4 cell count at 48 weeks was slightly higher in the nevirapine arm (596 vs. 569; P=0.1588). The number of patients with severe hypertriglyceridaemia (>400 mg/dL) after 48 weeks of treatment decreased in the nevirapine arm (from 11 to six), but increased in the PI arm (from four to 11) and led to treatment discontinuation in two patients. Lipodystrophy changes increased in 15% of patients in the PI arm but decreased in 4% of patients in the nevirapine arm. Finally, although adherence was similar in the two arms, patients reported that it required significantly less effort to stay on treatment in the nevirapine arm.

Conclusions

The results indicate that switching from PI to nevirapine is as effective as continuing with PI for maintaining viral control, even in patients with baseline viral load above 100 000 copies/mL. In addition, reductions in hypertriglyceridaemia and lipodystrophy and in the effort required to stay on treatment were observed.
Mitochondrial impairment induced by poly(ADP‐ribose) polymerase‐1 activation in cortical neurons after oxygen and glucose deprivation
Authors: Tanaka Seigo , Takehashi Masanori , Iida Shinya , Kitajima Takashi , Kamanaka Yoshihisa , Stedeford Todd , Banasik Marek , Ueda Kunihiro
Published: September 2005

Neuronal cells injured by ischemia and reperfusion to a certain extent are committed to death in necrotic or apoptotic form. Necrosis is induced by gross ATP depletion or ‘energy crisis’ of the cell, whereas apoptosis is induced by a mechanism still to be defined in detail. Here, we investigated this mechanism by focusing on a DNA damage‐sensor, poly(ADP‐ribose) polymerase‐1 (PARP‐1). A 2‐h oxygen and glucose deprivation (OGD) followed by reoxygenation (Reox) induced apoptosis, rather than necrosis, in rat cortical neurons. During the Reox, PARP‐1 was much activated and autopoly(ADP‐ribosyl)ated, consuming the substrate, NAD+. Induction of apoptosis by OGD/Reox was suppressed by overexpression of Bcl‐2, indicating mitochondrial impairment in this induction process. Mitochondrial permeability transition (MPT), or membrane depolarization, and a release of proapoptotic proteins, i.e. cytochrome c, apoptosis‐inducing factor and endonuclease G, from mitochondria were observed during the Reox. These apoptotic changes of mitochondria and the nucleus were attenuated by PARP‐1 inhibitors, 1,5‐dihydroxyisoquinoline and benzamide, and also by small interfering RNA specific for PARP‐1. These results indicated that PARP‐1 plays a principal role in inducing mitochondrial impairment that ultimately leads to apoptosis of neurons after cerebral ischemia.
Proteomic analysis of parkin knockout mice: alterations in energy metabolism, protein handling and synaptic function
Authors: Periquet Magali , Corti Olga , Jacquier Sandrine , Brice Alexis
Published: September 2005

Parkin knockout (KO) mice show behavioural and biochemical changes that reproduce some of the presymptomatic aspects of Parkinson's disease, in the absence of neuronal degeneration. To provide insight into the pathogenic mechanisms underlying the preclinical stages of parkin‐related parkinsonism, we searched for possible changes in the brain proteome of parkin KO mice by means of fluorescence two‐dimensional difference gel electrophoresis and mass spectrometry. We identified 87 proteins that differed in abundance between wild‐type and parkin KO mice by at least 45%. A high proportion of these proteins were related to energy metabolism. The levels of several proteins involved in detoxification, stress‐related chaperones and components of the ubiquitin–proteasome pathway were also altered. These differences might reflect adaptive mechanisms aimed at compensating for the presence of reactive oxygen species and the accumulation of damaged proteins in parkin KO mice. Furthermore, the up‐regulation of several members of the membrane‐associated guanylate kinase family of synaptic scaffold proteins and several septins, including the Parkin substrate cell division control related protein 1 (CDCRel‐1), may contribute to the abnormalities in neurotransmitter release previously observed in parkin KO mice. This study provides clues into possible compensatory mechanisms that protect dopaminergic neurones from death in parkin KO mice and may help us understand the preclinical deficits observed in parkin‐related parkinsonism.
Assessment of Agreement under Nonstandard Conditions Using Regression Models for Mean and Variance
Authors: Choudhary Pankaj K. , Tony Ng Hon Keung
Published: September 2005

Summary The total deviation index of Lin (2000, Statistics in Medicine19, 255–270) and Lin et al. (2002, Journal of the American Statistical Association97, 257–270) is an intuitive approach for the assessment of agreement between two methods of measurement. It assumes that the differences of the paired measurements are a random sample from a normal distribution and works essentially by constructing a probability content tolerance interval for this distribution. We generalize this approach to the case when differences may not have identical distributions—a common scenario in applications. In particular, we use the regression approach to model the mean and the variance of differences as functions of observed values of the average of the paired measurements, and describe two methods based on asymptotic theory of maximum likelihood estimators for constructing a simultaneous probability content tolerance band. The first method uses bootstrap to approximate the critical point and the second method is an analytical approximation. Simulation shows that the first method works well for sample sizes as small as 30 and the second method is preferable for large sample sizes. We also extend the methodology for the case when the mean function is modeled using penalized splines via a mixed model representation. Two real data applications are presented.
A general overview of burn care
Authors: Hermans Michel HE
Published: September 2005

The majority of burn victims do not need to be treated in a burn centre. Adequate care can be given by non specialised medical personnel, provided that proper guidelines are followed. The article outlines and reviews these guidelines.
GRB 050223: a faint gamma-ray burst discovered by Swift
Authors: Page K. L. , Rol E. , Levan A. J. , Zhang B. , Osborne J. P. , O'Brien P. T. , Beardmore A. P. , Burrows D. N. , Campana S. , Chincharini G. , Cummings J. R. , Cusumano G. , Gehrels N. , Giommi P. , Goad M. R. , Godet O. , Mangano V. , Tagliaferri G. , Wells A. A.
Published: September 2005

GRB 050223 was discovered by the Swift Gamma-Ray Burst Explorer on 2005 February 23 and was the first gamma-ray burst (GRB) to be observed by both Swift and XMM–Newton. At the time of writing (2005 May), it has one of the faintest GRB afterglows ever observed. The spacecraft could not slew immediately to the burst, so the first X-ray and optical observations occurred approximately 45 min after the trigger. Although no optical emission was found by any instrument, both Swift and XMM–Newton detected the fading X-ray afterglow. Combined data from both of these observatories show the afterglow to be fading monotonically as 0.99+0.15−0.12 over a time-frame between 45 min and 27 h post-burst. Spectral analysis, allowed largely by the higher throughput of XMM–Newton, implies a power law with a slope of Γ= 1.75+0.19−0.18 and shows no evidence for absorption above the Galactic column of 7 × 1020 cm−2.

From the X-ray decay and spectral slopes, a low electron power-law index of p= 1.3–1.9 is derived; the slopes also imply that a jet-break has not occurred up to 27 h after the burst. The faintness of GRB 050223 may be due to a large jet opening or viewing angle or a high redshift.
Measurement of CT radiation profile width using CR imaging plates
Authors: Liu Ho‐Ling , Liu Ruijie Rachel , Reeve Donna M. , Shepard S. Jeff , Willis Charles E.
Published: September 2005

This paper describes the procedure for using a Fuji computed radiography (CR) imaging plate (IP) for the measurement of computed tomography (CT) radiation profiles. Two sources of saturation in the data from the IP, signal and quantization, were characterized to establish appropriate exposure and processing conditions for accurate measurements. The IP generated similar profiles compared to those obtained from digitized ready‐pack films, except at the profile edges, where the exposure level is low. However, when IP pixel values are converted to exposure, CR and digitized film profiles are in agreement. The full width at half maximum (FWHM) of the CT radiation profile was determined from the relationship between pixel value and exposure and compared to FWHM of the digitized optical density profile from film. To estimate the effect of scattering by the cassette material, radiation profiles were acquired from IPs enclosed in a cassette or in a paper envelope. The presence of the cassette made no difference in the value determined for FWHM. With proper exposure and processing conditions, the FWHM of 5, 10, and 15 mm collimated beams were measured using IPs to be 7.1, 11.9, and 17.0 mm and using film to be 7.2, 12.2, and 16.8 mm, respectively. Our results suggest that, under appropriate conditions, the estimation of the width of the CT radiation profile using Fuji CR is comparable to the measurement from film density described in American Association of Physicists in Medicine (AAPM) Report No. 39. Although our experiment was conducted using Fuji CR, we anticipate that CR plates from other vendors could be successfully used to measure CT beam profiles because of similar empirical relationships between pixel value and exposure.
Experimental verification of a portal dose prediction model
Authors: van Elmpt W. J. C. , Nijsten S. M. J. J. G. , Mijnheer B. J. , Minken A. W. H.
Published: September 2005

Electronic portal imaging devices (EPIDs) can be used to measure a two‐dimensional (2D) dose distribution behind a patient, thus allowing dosimetric treatment verification. For this purpose we experimentally assessed the accuracy of a 2D portal dose prediction model based on pencil beam scatter kernels. A straightforward derivation of these pencil beam scatter kernels for portal dose prediction models is presented based on phantom measurements. The model is able to predict the 2D portal dose image (PDI) behind a patient, based on a PDI without the patient in the beam in combination with the radiological thickness of the patient, which requires in addition a PDI with the patient in the beam. To assess the accuracy of portal dose and radiological thickness values obtained with our model, various types of homogeneous as well as inhomogeneous phantoms were irradiated with a 6 MV photon beam. With our model we are able to predict a PDI with an accuracy better than 2% (mean difference) if the radiological thickness of the object in the beam is symmetrically situated around the isocenter. For other situations deviations up to 3% are observed for a homogeneous phantom with a radiological thickness of 17 cm and a 9 cm shift of the midplane‐to‐detector distance. The model can extract the radiological thickness within 7 mm (maximum difference) of the actual radiological thickness if the object is symmetrically distributed around the isocenter plane. This difference in radiological thickness is related to a primary portal dose difference of 3%. It can be concluded that our model can be used as an easy and accurate tool for the 2D verification of patient treatments by comparing predicted and measured PDIs. The model is also able to extract the primary portal dose with a high accuracy, which can be used as the input for a 3D dose reconstruction method based on back‐projection.
Progressive attenuation fields: Fast 2D‐3D image registration without precomputation
Authors: Rohlfing Torsten , Russakoff Daniel B. , Denzler Joachim , Mori Kensaku , Maurer Calvin R.
Published: September 2005

Computation of digitally reconstructed radiograph (DRR) images is the rate‐limiting step in most current intensity‐based algorithms for the registration of three‐dimensional (3D) images to two‐dimensional (2D) projection images. This paper introduces and evaluates the progressive attenuation field (PAF), which is a new method to speed up DRR computation. A PAF is closely related to an attenuation field (AF). A major difference is that a PAF is constructed on the fly as the registration proceeds; it does not require any precomputation time, nor does it make any prior assumptions of the patient pose or limit the permissible range of patient motion. A PAF effectively acts as a cache memory for projection values once they are computed, rather than as a lookup table for precomputed projections like standard AFs. We use a cylindrical attenuation field parametrization, which is better suited for many medical applications of 2D‐3D registration than the usual two‐plane parametrization. The computed attenuation values are stored in a hash table for time‐efficient storage and access. Using clinical gold‐standard spine image data sets from five patients, we demonstrate consistent speedups of intensity‐based 2D‐3D image registration using PAF DRRs by a factor of 10 over conventional ray casting DRRs with no decrease of registration accuracy or robustness.
Automatic exposure control for a slot scanning full field digital mammography system
Authors: Elbakri Idris A. , Lakshminarayanan A. V. , Tesic Mike M.
Published: September 2005

Automatic exposure control (AEC) is an important feature in mammography. It enables consistently optimal image exposure despite variations in tissue density and thickness, and user skill level. Full field digital mammography systems cannot employ conventional AEC methods because digital receptors fully absorb the x‐ray beam. In this paper we describe an AEC procedure for slot scanning mammography. With slot scanning detectors, our approach uses a fast low‐resolution and low‐exposure prescan to acquire an image of the breast. Tube potential depends on breast thickness, and the prescan histogram provides the necessary information to calculate the required tube current. We validate our approach with simulated prescan images and phantom measurements. We achieve accurate exposure tracking with thickness and density, and expect this method of AEC to reduce retakes and improve workflow.
4D rotational x‐ray imaging of wrist joint dynamic motion
Authors: Carelsen Bart , Bakker Niels H. , Strackee Simon D. , Boon Sjirk N. , Maas Mario , Sabczynski Jörg , Grimbergen Cornelis A. , Streekstra Geert J.
Published: September 2005

Current methods for imaging joint motion are limited to either two‐dimensional (2D) video fluoroscopy, or to animated motions from a series of static three‐dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x‐ray modalities and sophisticated 2D to 3D matching for the complex wrist joint. We present a method for the acquisition of dynamic 3D images of a moving joint. In our method a 3D‐rotational x‐ray (3D‐RX) system is used to image a cyclically moving joint. The cyclic motion is synchronized to the x‐ray acquisition to yield multiple sets of projection images, which are reconstructed to a series of time resolved 3D images, i.e., four‐dimensional rotational x ray (4D‐RX). To investigate the obtained image quality parameters the full width at half maximum (FWHM) of the point spread function (PSF) via the edge spread function and the contrast to noise ratio between air and phantom were determined on reconstructions of a bullet and rod phantom, using 4D‐RX as well as stationary 3D‐RX images. The CNR in volume reconstructions based on 251 projection images in the static situation and on 41 and 34 projection images of a moving phantom were 6.9, 3.0, and 2.9, respectively. The average FWHM of the PSF of these same images was, respectively, 1.1, 1.7, and orthogonal to the motion and parallel to direction of motion 0.6, 0.7, and . The main deterioration of 4D‐RX images compared to 3D‐RX images is due to the low number of projection images used and not to the motion of the object. Using 41 projection images seems the best setting for the current system. Experiments on a postmortem wrist show the feasibility of the method for imaging 3D dynamic joint motion. We expect that 4D‐RX will pave the way to improved assessment of joint disorders by detection of 3D dynamic motion patterns in joints.
Statistical cerebrovascular segmentation in three‐dimensional rotational angiography based on maximum intensity projections
Authors: Gan Rui , Wong Wilbur C. K. , Chung Albert C. S.
Published: September 2005

Segmentation of three‐dimensional rotational angiography (3D‐RA) can provide quantitative 3D morphological information of vasculature. The expectation maximization‐(EM‐) based segmentation techniques have been widely used in the medical image processing community, because of the implementation simplicity, and computational efficiency of the approach. In a brain 3D‐RA, vascular regions usually occupy a very small proportion (around 1%) inside an entire image volume. This severe imbalance between the intensity distributions of vessels and background can lead to inaccurate statistical modeling in the EM‐based segmentation methods, and thus adversely affect the segmentation quality for 3D‐RA. In this paper we present a new method for the extraction of vasculature in 3D‐RA images. The new method is fully automatic and computationally efficient. As compared with the original 3D‐RA volume, there is a larger proportion (around 20%) of vessels in its corresponding maximum intensity projection (MIP) image. The proposed method exploits this property to increase the accuracy of statistical modeling with the EM algorithm. The algorithm takes an iterative approach to compiling the 3D vascular segmentation progressively with the segmentation of MIP images along the three principal axes, and use a winner‐takes‐all strategy to combine the results obtained along individual axes. Experimental results on 12 3D‐RA clinical datasets indicate that the segmentations obtained by the new method exhibit a high degree of agreement to the ground truth segmentations and are comparable to those produced by the manual optimal global thresholding method.
Indirect flat‐panel detector with avalanche gain: Fundamental feasibility investigation for SHARP‐AMFPI (scintillator HARP active matrix flat panel imager)
Authors: Zhao Wei , Li Dan , Reznik Alla , Lui B. J. M. , Hunt D. C. , Rowlands J. A. , Ohkawa Yuji , Tanioka Kenkichi
Published: September 2005

An indirect flat‐panel imager (FPI) with avalanche gain is being investigated for low‐dose x‐ray imaging. It is made by optically coupling a structured x‐ray scintillator CsI(Tl) to an amorphous selenium (‐Se) avalanche photoconductor called HARP (high‐gain avalanche rushing photoconductor). The final electronic image is read out using an active matrix array of thin film transistors (TFT). We call the proposed detector SHARP‐AMFPI (scintillator HARP active matrix flat panel imager). The advantage of the SHARP‐AMFPI is its programmable gain, which can be turned on during low dose fluoroscopy to overcome electronic noise, and turned off during high dose radiography to avoid pixel saturation. The purpose of this paper is to investigate the important design considerations for SHARP‐AMFPI such as avalanche gain, which depends on both the thickness and the applied electric field of the HARP layer. To determine the optimal design parameter and operational conditions for HARP, we measured the dependence of both avalanche gain and optical quantum efficiency of an HARP layer. The results were used in a physical model of HARP as well as a linear cascaded model of the FPI to determine the following x‐ray imaging properties in both the avalanche and nonavalanche modes as a function of : (1) total gain (which is the product of avalanche gain and optical quantum efficiency); (2) linearity; (3) dynamic range; (4) gain nonuniformity resulting from thickness nonuniformity; and (5) effects of direct x‐ray interaction in HARP. Our results showed that a HARP layer thickness of can provide adequate avalanche gain and sufficient dynamic range for x‐ray imaging applications to permit quantum limited operation over the range of exposures needed for radiography and fluoroscopy.
Optimizing the acquisition time profile for a planar integral measurement system with a spinning slat collimator
Authors: Earl R. D. , Zeng G. L. , Zhang B.
Published: September 2005

This article considers a hypothetical imaging device with a spinning slat collimator that measures parallel‐planar‐integral data from an object. This device rotates around the object 180° and stops at positions uniformly distributed over this 180°. At each stop, the device spins on its own axis 180° and acquires measurements at positions uniformly distributed over this 180°. For a fixed total imaging time, an optimal distribution of the scanning time among the data measurement locations is searched by a nonlinear programming method: Nelder‐Mead's simplex method. The optimal dwell time is approximately proportional to the weighting factor in the backprojector of the reconstruction algorithm. By using an optimal dwell‐time profile, the reconstruction signal‐to‐noise ratio has a gain of 23%–24% for the filtered backprojection algorithm and a gain of 10%–18% for the iterative algorithms, compared with the situation when a constant dwell‐time profile is used.
The impact of thermal wave characteristics on thermal dose distribution during thermal therapy: A numerical study
Authors: Shih Tzu‐Ching , Kou Hong‐Sen , Liauh Chihng‐Tsung , Lin Win‐Li
Published: September 2005

The aim of this study was to investigate the effects of the propagation speed of a thermal wave in terms of the thermal relaxation time on the temperature/thermal dose distributions in living tissue during thermal therapies. The temperature field in tissue was solved by the finite difference method, and the thermal dose was calculated from the formulation proposed by Sapareto and Dewey [Int. J. Radiat. Oncol. Biol. Phys. 10, 787–800 (1984)]. Under the same total deposited energy, for a rapid heating process the time lagging behavior of the peak temperature became pronounced and the level of the peak temperature was decreased with increasing the thermal relaxation time. When the heating duration was longer than the thermal relaxation time of tissues, there was no significant difference between the thermal dose distributions with/without considering the effect of the thermal relaxation time. In other words, when the heating duration is comparable to or shorter than the thermal relaxation time of tissue, the results of the wave bioheat transfer equation (WBHTE) are fully different from that of the Pennes’ bioheat transfer equation (PBHTE). Besides, for a rapid heating process the dimension of thermal lesion was still significantly affected by perfusion, because this is what is predicted by the WBHTE but not by the PBHTE, i.e., the wave feature of the temperature field cannot fully be predicted by the PBHTE.
Influence of ion chamber response on in‐air profile measurements in megavoltage photon beams
Authors: Tonkopi E. , McEwen M. R. , Walters B. R. B. , Kawrakow I.
Published: September 2005

This article presents an investigation of the influence of the ion chamber response, including buildup caps, on the measurement of in‐air off‐axis ratio (OAR) profiles in megavoltage photon beams using Monte Carlo simulations with the EGSnrc system. Two new techniques for the calculation of OAR profiles are presented. Results of the Monte Carlo simulations are compared to measurements performed in 6, 10 and photon beams produced by an Elekta Precise linac and shown to agree within the experimental and simulation uncertainties. Comparisons with calculated in‐air kerma profiles demonstrate that using a plastic mini phantom gives more accurate air‐kerma measurements than using high‐ material buildup caps and that the variation of chamber response with distance from the central axis must be taken into account.
Evaluation of a computed radiography system for megavoltage photon beam dosimetry
Authors: Olch Arthur J.
Published: September 2005

Computed radiography (CR) systems have been gaining adoption as digital replacements for film for diagnostic and therapy imaging. As a result, film processors are being removed from service, leaving a void for the medical physicists who use film and processors for two‐dimensional megavoltage beam dosimetry. This is the first report to evaluate the ability of a commercial CR reader and storage phosphor plate system to accurately quantitate absolute dose and dose distributions from a 6 MV photon beam. There are potential advantages and disadvantages of current CR systems compared to film systems. CR systems inherently produce a linear dose‐response over several logs of dose. However, the barium in the storage phosphor has a higher atomic number than the silver in film, resulting in significant energy sensitivity. The purpose of this work is to fully characterize the impact of these and other features of this CR system relevant to dosimetry. The tests performed and reported on in this study include uniformity of readout across a uniform field, geometrical accuracy, intra‐ and interday reproducibility, signal decay with time and with light exposure, dose‐to‐signal calibration, high dose effects, obliquity effects, perpendicular and parallel calibration results, field size and depth of measurement effects and the use of lead filters to minimize them, and intensity modulated radiation therapy quality assurance test results compared to that for film. Practical techniques are provided to optimize the accuracy of the system as a dosimetric replacement for film.
A novel magnetic method for examination of bowel motility
Authors: Andrä Wilfried , Danan Henri , Eitner Klaus , Hocke Michael , Kramer Hans‐Helmar , Parusel Henry , Saupe Pieter , Werner Christoph , Bellemann Matthias E.
Published: September 2005

In contrast to the well‐developed methods for morphological diagnosis of the gastrointestinal tract, there is no comparatively satisfying technique for functional disorders. One important example is irritable bowel syndrome (IBS), a disorder that affects a high percentage of all individuals. It can only be diagnosed by excluding organic diseases and by considering symptom criteria. In this case, the examination of the motility of the bowel may be a promising way to differentiate between the two major mechanisms of IBS: increased sensitivity of the intestine and altered gastrointestinal motility. To this aim, a recently developed method for monitoring magnetic markers in the gastrointestinal tract was utilized that works without the use of ionizing radiation. We give a short description of this method, showing a spatial resolution of and a temporal resolution of , and report on examples of the first in vivo experiments. Typical monitoring results are shown for the esophagus, the stomach, and the duodenum. The motility behavior is described for the lower parts of the gut as well. The advantages and drawbacks of this type of magnetic marker monitoring are discussed with special consideration of the noninvasive examination of the motility in different sections of the gut.
Examination of dosimetry accuracy as a function of seed detection rate in permanent prostate brachytherapy
Authors: Su Yi , Davis Brian J. , Herman Michael G. , Manduca Armando , Robb Richard A.
Published: September 2005

The variation of permanent prostate brachytherapy dosimetry as a function of seed detection rates was investigated for I125 implants with seed activities commonly employed in contemporary practice. Post‐implant imaging and radiation dosimetry data from nine patients who underwent PPB served as the basis of this simulation study. One‐thousand random configurations of detected seeds were generated for each patient dataset using various seed detection levels from 30% to 99%. Dose parameters, including D90, were computed for each configuration and compared with the actual dosimetry data. A total of 108 000 complete sets of post‐PPB dose volume statistics were computed. The results demonstrated that although the average D90 differed from the true value by less than 5% when 70% or more seeds were identified, the D90 of an individual case could deviate up to 13%. The 95% confidence interval (CI) of estimated D90 values differ by less than 5% from the actual value when 95% or more seeds are detected, or approximately a difference in the D90 value for a prescription dose of . Estimated target volume dose parameters tended to decrease with reduced seed detection rates. The most variable dose parameter was the prostate V100 in absolute scale while the urethral V100 was most variable in a relative sense. Based on this comprehensive simulation study, it is suggested that 95% or more seeds need to be localized in order to provide an accurate estimation of dose parameters for contemporary iodine 125 permanent prostate brachytherapy.
LNFPIII/LeX-Stimulated Macrophages Activate Natural Killer Cells via CD40-CD40L Interaction
Authors: Atochina Olga , Harn Donald
Published: September 2005

Lacto-N-fucopentaose III (LNFPIII) is a human milk sugar containing the biologically active Lewis X (LeX) trisaccharide. LNFPIII/LeX is also expressed by immunosuppressive helminth parasites, by bacteria, and on a number of tumor/cancer cells. In this report, we first demonstrate that LNFPIII activates macrophages in vitro as indicated by upregulation of Gr-1 expression on F4/80+cells. Further, we investigated the effect of LNFPIII-activated macrophages on NK cell activity. We found that LNFPIII-stimulated F4/80+cells were able to activate NK cells, inducing upregulation of CD69 expression and gamma interferon (IFN-γ) production. The experiments show that NK cell activation is macrophage dependent, since NK cells alone did not secrete IFN-γ in response to LNFPIII. Furthermore, we found that activation of NK cells by glycan-stimulated macrophages required cell-cell contact. As part of the cell-cell contact mechanism, we determined that CD40-CD40L interaction was critical for IFN-γ secretion by NK cells, as the addition of anti-CD40L antibodies to the coculture blocked IFN-γ production. We also demonstrated that LNFPIII-stimulated macrophages secrete prostaglandin E2, interleukin-10 (IL-10), and tumor necrosis factor alpha (TNF-α) but a very low level of IL-12. Interestingly, addition of anti-TNF-α, anti-IL-10, or anti-IL-12 monoclonal antibodies did not significantly alter NK cell activity. Our data show that these soluble mediators are not critical for LNFPIII-stimulated macrophage activation of NK cells and provide further evidence for the importance of cell-cell contact and CD40-CD40L interactions between macrophages and NK cells.
Diagnosis of Tetanus Immunization Status: Multicenter Assessment of a Rapid Biological Test
Authors: Colombet Isabelle , Saguez Colette , Sanson-Le Pors Marie-José , Coudert Benoît , Chatellier Gilles , Espinoza Pierre ,   the Scientific Committee of the TetaQuick 1000 Study
Published: September 2005

Diagnosis of tetanus immunization status by medical interview of patients with wounds is poor. Many protected patients receive unnecessary vaccine or immunoglobulin, and unprotected patients may receive nothing. The aim of this study is to evaluate the feasibility and accuracy of the Tetanos Quick Stick (TQS) rapid finger prick stick test in the emergency department for determining immunization status. We designed a prospective multicenter study for blinded comparison of TQS with an enzyme-linked immunosorbent assay (ELISA). Adults referred for open wounds in 37 French hospital emergency departments had the TQS after receiving standard care (emergency-TQS). TQS was also performed in the hospital laboratory on total blood (blood/lab-TQS) and serum (serum/lab-TQS). ELISA was performed with the same blood sample at a central laboratory. We assessed concordance between emergency-TQS and blood/lab-TQS by the kappa test and the diagnostic accuracy (likelihood ratios) of medical interview, emergency-TQS, and lab-TQS. ELISA was positive in 94.6% of the 988 patients included. Concordance between blood/emergency-TQS and blood/lab-TQS results was moderate (κ = 0.6), with a high proportion of inconclusive blood/emergency-TQS tests (9.8%). Likelihood ratios for immunization were 3.0 (95% confidence interval [CI], 1.8 to 5.1), 36.6 (95% CI, 5.3 to 255.3), 89.1 (95% CI, 5.6 to 1,405.0), and 92.7 (95% CI, 5.9 to 1,462.0) for medical interview, blood/emergency-TQS, blood/lab-TQS, and serum/lab-TQS, respectively. The sensitivity of the blood/emergency-TQS was 76.7%, and the specificity was 98% by reference to the ELISA. TQS use in the emergency room could make tetanus prevention more accurate if its technical feasibility were improved, and our assessment will be supplemented by a cost effectiveness study.
Endogenous Superantigens Shape Response to Exogenous Superantigens
Authors: Rajagopalan Govindarajan , Singh Manisha , Sen Moon M. , Murali Narayana S. , Nath Karl A. , David Chella S.
Published: September 2005

Endogenous superantigen-mediated thymic negative selection resulted in a paucity of mature T cells bearing T-cell receptor (TCR) Vβ8 in the periphery. Consequently, the magnitude of immune response to exogenous superantigen staphylococcal enterotoxin B, which activates TCR Vβ8
+
T cells, was significantly reduced and conferred protection from superantigen-induced mortality.
Patients with Pulmonary Tuberculosis Develop a Strong Humoral Response against Methylated Heparin-Binding Hemagglutinin
Authors: Zanetti Stefania , Bua Alessandra , Delogu Giovanni , Pusceddu Cinzia , Mura Maristella , Saba Franca , Pirina Piero , Garzelli Carlo , Vertuccio Cono , Sechi Leonardo A. , Fadda Giovanni
Published: September 2005

Reactivities of human sera against selected recombinant
Mycobacterium tuberculosis
antigens were assessed by enzyme-linked immunosorbent assay. The results obtained indicate that patients with tuberculosis (TB) do not develop a strong humoral response against PE_PGRS and PPE proteins or against the Ag85B and heparin-binding hemagglutinin (HBHA) recombinant antigens. Conversely, purified methylated HBHA was strongly recognized by sera obtained from TB patients compared to controls.
Clinical Utility of Commercial Enzyme Immunoassays during the Inaugural Season of West Nile Virus Activity, Alberta, Canada
Authors: Tilley Peter A. G. , Walle Roberta , Chow Anthony , Jayaraman Gayatri C. , Fonseca Kevin , Drebot Michael A. , Preiksaitis Jutta , Fox Julie
Published: September 2005

West Nile virus (WNV) has spread rapidly across North America, creating a need for rapid and accurate laboratory diagnosis on a large scale. Immunoglobulin M (IgM) capture enzyme immunoassays (EIA) became commercially available in the summer of 2003, but limited data are available on their clinical performance. Consolidated human WNV diagnostic testing for the province of Alberta, Canada, at the public health laboratory permitted a large-scale evaluation of the assays, covering a wide clinical spectrum. Two thousand nine hundred sixty-nine sera were tested, from 2,553 Alberta residents, and 266 cases were identified. Sensitivities of the Focus assay and first-generation Panbio IgM capture EIA were 79 and 80%, respectively. During the first week of illness only 53 to 58% of cases were positive, but sensitivity was 96 to 97% after day 8. Sensitivity for neurological cases was 92% overall. Specificity was high for the Focus kit at 98.9%, but only 82.9% for the first Panbio kit. A positive Focus WNV IgG result with a twofold rise in IgG index was a reliable indicator of acute flavivirus infection (67/67 WNV). Agreement between the IgG test and hemagglutinin inhibition titers in paired sera was at least 82%. Commercial IgM and IgG EIA proved useful for WNV diagnosis, provided follow-up sera were collected after 8 days of illness.
Mumps Virus-Specific Antibody Titers from Pre-Vaccine Era Sera: Comparison of the Plaque Reduction Neutralization Assay and Enzyme Immunoassays
Authors: Mauldin Jeremy , Carbone Kathryn , Hsu Henry , Yolken Robert , Rubin Steven
Published: September 2005

Mumps virus-neutralizing antibodies are believed to be the most predictable surrogate marker of protective immunity. However, assays used to detect neutralizing antibodies, such as the plaque reduction neutralization (PRN) assay, are labor- and time-intensive and consequently are often supplanted by the more rapid and inexpensive enzyme immunoassay (EIA) technique. For virus infections for which international antibody standards exist and are bridged to clinical studies of protection (e.g., measles and rubella), the EIA has been successfully used to determine immune surrogate endpoints, yet no such international reference exists for mumps serology. Since both virus-neutralizing and nonneutralizing antibodies are measured in the EIA, in the absence of a mumps serological standard, the EIA may be prone to yielding false-positive results when utilized for assessing surrogate markers of protective immunity. Moreover, since mumps virus-specific antibody titers are generally low in comparison to antibody levels induced by other viruses and EIA procedures often employ relatively high serum dilution factors, the EIA may be prone to yielding false-negative results. To examine these issues, a PRN assay and two commercially available EIA kits were used to evaluate wild-type mumps virus serological responses in human serum samples from the pre-mumps vaccine era. Our results indicate that the PRN assay is a more sensitive and specific method of measuring serological responses to wild-type mumps virus.
Extrinsic Allergic Alveolitis (Hypersensitivity Pneumonitis) Caused by
Sphingobacterium spiritivorum
from the Water Reservoir of a Steam Iron
Authors: Kämpfer Peter , Engelhart S. , Rolke M. , Sennekamp J.
Published: September 2005

A case of extrinsic allergic alveolitis (EAA) caused by
Sphingobacterium spiritivorum
is described. The symptoms were associated with the use of a steam iron. The water reservoir was heavily contaminated with
S. spiritivorum
(10
6
CFU ml
−1
). This is the first report of
S. spiritivorum
as a causative agent of EAA.
Posttranslational Protein Modification inArchaea
Authors: Eichler Jerry , Adams Michael W. W.
Published: September 2005

One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized inEucaryaandBacteria, posttranslational modification inArchaeahas received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered byArchaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification inArchaeaform the focus of this review.