Somatosensory evoked responses via electronic brain imaging (EBI).

This study of a series of 40 mildly head injured (concussed) patients suggests that different physiologic pathways underlying the tests done in a six-part resting EEG, and for the 11 evoked electrical potential shifts occurring in the cerebral terrain, are testable. Further work seems likely in order to ascertain which clinical signs and symptoms may be related to specific individual types of recorded electronic brain imaging (EBI) abnormality. Which of the 11 parameters studied, EEG, VER, AER, and SER, would be more or less likely to be abnormal in their individual patterns (as being deviant from normal controls) also remains to be defined. The relationship of these neurophysiologic abnormalities to certain postconcussive symptoms, i.e., headache, dizziness, blurred vision, etc., at this point in time remains to be evaluated more precisely. The authors suggest that further research is necessary in evaluating the clinical use of somatosensory evoked responses as an additional parameter in electronic brain imaging (EBI) technology.     

Measurement of Pressure-Time Product during Spontaneous Assisted Breathing by Rapid Interrupter Technique

Background: Measuring the work of breathing of patients undergoing spontaneous assisted ventilation can be useful to monitor and titrate ventilatory support. The aim of this study was to obtain measurements of the pressure generated by the respiratory muscles (PMUSC) and the derived pressure-time product (PTP; a good indicator of the metabolic work of breathing), performing the rapid interrupter technique with a commercial ventilator.

Methods: A Draeger Evita 4 ventilator (Draeger Medical, Lubeck, Germany) was controlled by a personal computer to rapidly interrupt the airway flow at different times and volumes of the respiratory cycle during pressure-support ventilation. From the airway pressure tracing after the occlusion, the authors estimated the alveolar pressure and PMUSC; the integration of PMUSC values over the inspiratory time yields the measurement of PTP. Esophageal pressure measurements were used as a reference. After a bench study of the valves' performance, the authors performed 11 measurement sequences in eight patients.

Results: The closure times for the inspiratory and expiratory valves were 74 +/- 10 and 61 +/- 13 ms, respectively. The interrupter technique provided a reliable estimate of PMUSC (PMUSC, occl = 1.00 [middle dot] PMUSC, pes + 0.19; r = 0.88; 95% confidence interval for agreement, +5.49/-5.32 cm H2O). PTPoccl tightly correlated with PTPpes (PTPoccl = 0.95 [middle dot] PTPpes + 0.13; r = 0.96; 95% confidence interval, 1.94/-1.61 cm H2O [middle dot] s).     

RF refocused echoes of J-coupled spin systems: effects on RARE-based spectroscopic imaging.

A numerical simulation tool was developed to calculate the echo amplitudes of J-coupled resonances within a series of radiofrequency (RF) refocused echoes. The signal modulation due to J-coupling in rapid acquisition with relaxation enhancement (RARE) is suppressed only when the inverse of the pulse interval (tau) is large compared to both the chemical shift (CS) difference (Deltadelta) of the coupled spins and the coupling constant. In contrast, the echo amplitudes in ultrafast low-flip-angle RARE (U-FLARE) oscillate around a quasi-steady-state value that is greater than zero (neglecting relaxation and diffusion) even when Deltadelta > 1/tau. The flip-angle distribution over the measured slice caused by the use of Gaussian-shape slice-selective refocusing pulses further reduces the echo oscillations. When the pulse interval falls short of the fast pulse rate regime, spectroscopic U-FLARE provides an improved spatial impulse response in the phase-encoding (PE) direction compared to spectroscopic RARE.     

18F-FDG PET for mediastinal staging of lung cancer: which SUV threshold makes sense?

(18)F-FDG PET is the most accurate noninvasive modality for staging mediastinal lymph nodes in lung cancer. Besides using visual image interpretation, some institutions use standardized uptake value (SUV) measurements in lymph nodes. Mostly, an SUV of 2.5 is used as the cutoff, but this choice was never deduced from respective studies. Receiver operating characteristic (ROC) analyses demonstrated that SUV thresholds of more than 4 resulted in the highest accuracy. But these high cutoffs imply high false-negative rates (FNRs). The aim of our evaluation was to determine an optimal SUV threshold and to compare its diagnostic performance with the results of visual interpretation. METHODS: This retrospective study included 95 patients with suspected lung cancer who underwent mediastinoscopy/mediastinal lymphadenectomy after (18)F-FDG PET (90-150 min after 250 MBq of (18)F-FDG). Maximum SUV was measured in 371 lymph node regions biopsied afterward and visually interpreted using a 6-level score (- - - through + + +). Diagnostic performance was assessed by ROC analysis. FNR and false-positive rate (FPR), the sum of both error rates (FNR + FPR), and diagnostic accuracy were plotted against a hypothetical SUV threshold to determine the optimum SUV threshold. RESULTS: SUVs in metastatic lymph nodes were higher (mean +/- SD, 7.1 +/- 4.5; range, 1.4-26.9; n = 70) than in tumor-free lymph node stations (2.4 +/- 1.7; range, 0.6-14.9; n = 301; P < 0.01). Inflammatory lymph nodes exhibited slightly increased SUVs (2.7 +/- 2.0; range, 0.8-14.9; n = 146). The plot of error rates featured a minimum of the sum FNR + FPR for an SUV of 2.5. With increasing SUV threshold, the FPR decreased most prominently up to that value whereas a continuous rise of FNR was noticed. Highest diagnostic accuracy was achieved with an SUV of 4.5. The areas under the ROC curves demonstrated that visual interpretation tends to be more accurate than SUV quantification (visual, 0.930 +/- 0.022; SUV, 0.899 +/- 0.025; P = 0.241). Using an SUV of 2.5 as the threshold, the resulting sensitivity, specificity, and negative predictive value were 89%, 84%, and 96%, respectively. CONCLUSION: For mediastinal staging, the choice of an SUV of 2.5 as the threshold is justified because FNR + FPR is minimized. The resulting high negative predictive value of 96% allows the omission of mediastinoscopy in patients with negative mediastinal findings on (18)F-FDG PET images. For the experienced observer, visual analysis should be relied on primarily, with calculation of the SUV used, at most, as a secondary aid. For the less experienced observer, the SUV may be of greater value.     

PgH2 analogs as potential antiplatelet derivatives.

Previous observations implicating PgH2 as a direct activator of platelets suggested that derivatives of U46619, a well-characterized TxA2 receptor agonist having structural homology with PgH2, might possess antiplatelet activity. The present work describes the synthesis of [1S-(1 alpha,2 beta,3 alpha,4 alpha)]-3-[(tetrahydropyranyloxy)methyl]- 2-[2-[(triphenylmethyl)oxy]ethyl]-5-oxabicyclo[2.2.1]heptane (14) a potentially useful intermediate for the synthesis of various epoxymethano derivatives. The latter was converted to [1S-(1 alpha,2 beta (Z),3 alpha,4 alpha)]-7-[3-[[2- [(phenylamino)carbonyl]-hydrazino]methyl]-5-oxabicylo[2.2.1]hept-2 - yl]-5-heptenoic acid (23), an epoxymethano derivative of PgH2 containing a hydrazide lower side chain as previously used in the TxA2 antagonist, SQ 29,548. The intermediate 14 was also converted to [1S-(1 alpha,2 beta (Z),3 alpha,4 alpha)]-7- [3-[(hexylamino)methyl]-5-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid (25) which contained a simple aza side chain as used in earlier antagonists. Derivatives 23 and 25 appeared to be specific antagonists of the human platelet TxA2 receptor as evidenced by their inhibition of U46619 (1.5 microM) induced aggregation of human platelet rich plasma (IC50 = 22 and 7 microM, respectively), while having little effect on ADP (2 microM) induced aggregation at much higher concentrations. In addition, one of these derivatives, the bicycloamine 25, was shown to compete for [3H]U46619 binding to washed human platelets with an IC50 value of 25 microM, supporting the notion that these derivatives were acting at the thromboxane receptor. However, the potency of these derivatives was less than for previously reported TxA2 antagonists, suggesting that simple linear combinations of functionality from molecules active at the human platelet thromboxane receptor will be of limited predictive value.     

Posterior Cervical-Thoracic Thermograms: Pattern Persistence and Correlation with Chronic Headache Syndromes

SYNOPSIS
These experiments investigate thermographic patterns in the posterior cervical/thoracic (PCT) region of 530headache patients and 30 headache/injury-free volunteers. The study examines: The longitudinal persistence ofProximal and Distal patterns; three distinct midline patterns (PCT I, II, and III); and their correlation with diagnosis,injury, and pain.
Twenty-four (80%) of 30 randomly selected subjects displayed unchanged Proximal patterns at the meanobservation period of 5.5 months. PCT pattern fluctuations occurred in 13/30 (43.3%) subjects. The distinctivenessof each subject's Proximal and Distal patterns was verified by blind calling of thermogram pairs. Patternpersistence was validated with alcohol spray-Patterns were identical regardless of using a 0.5°C or 1.0°Ctemperature setting. Temperature settings of 1.0°C yielded more distinct Proximal and Distal patterns.
Chi square analysis determined that there was no significant difference in the number of PCT III patterns in theexperimental or control groups.
In conclusion, it appears that Proximal and Distal Patterns may be consistent over time and individually unique,but that PCT patterns fluctuate and, therefore, do not correlate with chronic headaches.     

Safety of virus inactivated antithrombin III concentrate ANTITHROMBIN III IMMUNO (AT III)

In a prospective clinical trial the risk of infection after application of virus inactivated antithrombin III concentrate ANTITHROMBIN III IMMUNO (AT III) was investigated in patients undergoing cardiovascular surgery. The study was conducted according to the recommendations of the International Committee on Thrombosis and Hemostasis (ICTH), with the exception that most patients required additional blood products as well as AT III.

Twenty-seven patients were eligible to test for the risk of acquiring hepatitis B. Twenty-six patients could be evaluated in terms of hepatitis NANB transmission considering ALT-levels whereas 20 patients could be tested for anti-HCV one year after surgery. Samples from 78 patients could be monitored for anti-HIV-1. None of these patients showed any signs of infection. AT III IMMUNO seems to be an antithrombin III concentrate with low or absent infectivity.