Recent research has implicated a large number of gluten-derived peptides in the pathogenesis of celiac disease, a preponderantly HLA-DQ2-associated disorder. Current evidence indicates that the core ...of some of those peptides is ten amino acids long, while HLA class II normally accommodates nine amino acids in the binding groove. We have now investigated this in detail, using gluten-specific T-cell clones, HLA-DQ2-specific peptide-binding assays and molecular modelling. T-cell recognition of both a gamma-gliadin peptide and a low-molecular-weight glutenin peptide was found to be strictly dependent on a ten-amino acids-long peptide. Subsequent peptide-binding studies indicated that the glutenin peptide bound in a conventional p1/p9 register, with an additional proline at p-1. Testing of substitution analogues demonstrated that the nature of the amino acid at p-1 strongly influenced T-cell recognition of the peptide. Moreover, molecular modelling confirmed that the glutenin peptide binds in a p1/p9 register, and that the proline at p-1 points upward towards the T-cell receptor. Database searches indicate that a large number of potential T-cell stimulatory gluten peptides with an additional proline at relative position p-1 exist, suggesting that the recognition of other gluten peptides may depend on this proline as well. This knowledge may be of importance for the identification of additional T-cell stimulatory gluten peptides and the design of a peptide-based, tolerance-inducing therapy.
PURPOSE:To assess the emphysematous enlargement of distal airspaces and concomitant large and small airway disease using diffusion-weighted Helium-magnetic resonance imaging (MRI), high-resolution ...computed tomography (HRCT), and lung function tests (LFT).
METHODS:Seven patients were examined after single lung transplantation (LTx) and 1 before double LTx for various forms of emphysema. Five patients after double LTx served as controls. Patients were assessed by Helium-MRI (apparent diffusion coefficient ADC), HRCT (mean lung density MLD, emphysema index EI), and LFT.
RESULTS:Transplanted lungsmean ADC = 0.17 cm/s, MLD = −848 H, EI = 22%. Emphysematous lungsmean ADC = 0.33 cm/s, MLD = −922 H; EI = 54%. Good correlations were found between ADC and MLD (r = 0.6), EI (r = 0.8), intrathoracic gas volume (r = 0.7), forced expiratory volume in 1 second (r = 0.7), and forced expiratory flows (r = 0.7). In contrast, HRCT only provided moderate correlations with LFT (EIr = 0.5; MLDr le 0.4).
CONCLUSION:In this initial study, He-MRI yield good correlations with HRCT and agrees better than HRCT with the functional characterization of emphysema regarding hyperinflation, large and small airway disease as provided by LFT.
Ziele:
Fluorinierte Gase wie Schwefelhexafluorid (SF6) können für Untersuchungen der Ventilation der Lunge mittels MRT eingesetzt werden. Da hier auf ein aufwändiges Polarisationsverfahren verzichtet ...werden kann, ist der technische Aufwand wesentlich geringer als beispielsweise bei der Lungenbildgebung mittels Helium-3. Ziel der vorliegenden Studie war die Untersuchung der Reproduzierbarkeit von Wash-in-Experimenten und die Erforschung des Zusammenhangs zwischen der Signalintensität und der exspiratorischen SF6-Konzentration von SF6-O2-Gemischen.
Methode:
Fünf anästhesierte Hausschweine (19,2±1,8kg) wurden je fünfmal mit Gasgemischen von 30% Sauerstoff und 70% SF6 beatmet. Mittels 19F-MRT wurden alle zwei Atemzüge Bilder des Wash-in-Vorgangs aufgenommen. Die Messzeit der 19F-Sequenz betrug 10 s pro Bild. Als Referenzmethode wurde simultan die exspiratorische SF6-Konzentration mittels Atemgasmonitor erfasst. Mittlere Signalintensitäten und Atemgas-Daten wurden hinsichtlich Reproduzierbarkeit und Korrelation analysiert
Ergebnis:
Die mittleren Variationskoeffizienten waren für die 19F-MRT (7,6%±3,3%) nur geringfügig höher als für die Daten aus der Atemgasanalyse (5,4%±2,2%). Signalintensitäten und SF6-Konzentrationen zeigten eine hohe Korrelation (R
2
=0,98%±0,2). Als Nebenergebnis fanden wir eine signifikante Verzögerung des Einwaschvorgangs durch das gewählte Applikationssystem.
Schlussfolgerung:
Das Applikationssystem ermöglicht eine verzögerte, aber gut reproduzierbare Applikation des SF6-Gases. Die Reproduzierbarkeit der 19F-MRT war hoch.
We propose a renal imaging agent, the
99mTc complex of the bidentate-
N,S chelate
N-(mercaptoacetyl) glycine (
99mTc-2GAM), with the imaging characteristics of
99mTc-DMSA but a faster kidney uptake; ...chemical evidence supports the formulation of
99mTc-2GAM as Tc
V(O)(GAM)
2
−. After biodistribution and toxicity studies in animals,
99mTc-2GAM was evaluated in five normal volunteers.
99mTc-2GAM is rapidly cleared from the blood (
t
1
2
= 9
min
) and 50% of the ID is excreted in the urine in the first 2 h. Dynamic data show a rapid renal uptake that increases up to 1 h with no significant wash-out between 1 and 8 h. The uptake in each kidney ranges from 11.3% to 20.7% ID. Low, stable liver uptake is observed. No significant activity is detected in other organs. We showed no differences between
99mTc-2GAM and
99mTc-DMSA compared in three patients with unilateral kidney disease. We conclude that
99mTc-2GAM has good practical and dosimetric features for renal imaging.
The reliability of a ternary Sn/Ag/Cu alloy for flip chip solder joints will be reported in this paper. Dominant failure mechanisms for given thermal stress regimes are well defined for 63Sn/Pb ...eutectic solder. Characterizing Sn/Ag/Cu solder reliability in comparison to 63Sn/Pb solder provides a true baseline for these thermal stress regimes and still allows for a broad search of mechanisms due to the change in alloy properties inherent in this new metallurgic system. Reliability characterization must examine both solder bump and under bump metallization (UBM) robustness, because the interaction between the two contributes to the overall efficacy of the structure. Reported in this work are thermal cycle, high temperature storage, and die shear test results demonstrating the solder bump reliability. Electromigration, multiple reflow, and bare die high temperature test results verifying the UBM robustness are also presented. In addition, the assembly-related details are reported in an effort to provide a foundation for improved yield.
For two linear experiments d1= L(X1β, V1) and d2= L(X2β, V2) where the covariances V1and V2are known and can be singular or nonsingular, we characterize the following relations: d1at least as good as ...d2, d1better than d2, and d1equivalent to d2. Sometimes only a subset of parameters is of interest to the experimenter. We extend the above relations between d1and d2to estimation of a common subset of parameters and give analogous characterizations. Three examples are given.
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