The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, ...separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe<6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe<7×10−13 at 90% CL set by the SINDRUM II experiment.
The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, ...separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe<6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe<7×10−13 at 90% CL set by the SINDRUM II experiment.
Fibrin sealants (FS) derived from human plasma are frequently used in neurosurgery. In order to increase clot stability, FS typically contain aprotinin, a natural fibrinolysis inhibitor. Recently, ...synthetic fibrinolysis inhibitors such as tranexamic acid (tAMCA) have been considered as substitutes for aprotinin. However, tAMCA has been shown to cause epileptic seizures. We wanted to study whether tAMCA retains its convulsive action if incorporated into a FS.
FS containing aprotinin or different concentrations of tAMCA (0.5-47.5 mg/ml) were applied to the pial surface of the cortex of anaesthetized rats. The response of the animals was evaluated using electroencephalography and by monitoring the clinical behaviour during and after recovery from anaesthesia.
FS containing tAMCA caused paroxysmal brain activity which was associated with distinct convulsive behaviours. The degree of these seizures increased with increasing concentration of tAMCA. Thus, FS containing 47.5 mg/ml tAMCA evoked generalized seizures in all tested rats (n=6) while the lowest concentration of tAMCA (0.5 mg/ml) only evoked brief episodes of jerk-correlated convulsive potentials in 1 of 6 rats. In contrast, FS containing aprotinin did not evoke any paroxysmal activity.
Tranexamic acid retains its convulsive action within FS. Thus, use of FS containing tAMCA for surgery within or close to the CNS may pose a substantial risk to the patient.
Respiratory failure is a common and potentially life threatening complication in patients with Guillain-Barré syndrome. The incidence of phrenic nerve involvement and the predictive value of phrenic ...nerve conduction and diaphragmatic needle EMG were studied in 40 patients with Guillain-Barré syndrome within the first three days of admission to hospital. The negative peak onset latency of the diaphragmatic compound muscle action potential (CMAP), and its amplitude, duration, and area were abnormal in 83%. The need for ventilation was correlated with diaphragmatic CMAP amplitude (P = 0.005), and area (P = 0.001), but not with latency or duration. Abnormalities in diaphragmatic needle EMG were found in 45%, mainly a decreased number of motor unit potentials. The abnormalities correlated with the need for ventilation (P = 0.013). Of the 40% who required ventilation, all had either abnormal phrenic conduction, abnormal diaphragmatic needle EMG, or both. Eighty one per cent of the ventilated patients had abnormal forced vital capacity on the day of the electrophysiological examination. The results indicate that phrenic nerve conduction studies and diaphragmatic EMG are useful in detecting respiratory involvement in patients with Guillain-Barré syndrome and in identifying those at risk of respiratory failure.
Respiratory electrophysiological studies are of essential value in diagnosing and managing patients with respiratory failure, but assessment of the sensory phrenic nerve fibres has been neglected. We ...recorded phrenic nerve somatosensory evoked potentials (SSEPs) by combining neurophysiological and neuroimaging techniques in three healthy subjects. Evoked potentials of the phrenic nerve showed the highest amplitude at CP3, determined by the modified 10–20 EEG system, and occurred at a constant latency, PI at 12.0 ± 0.6 ms, and NI at 17.3 ± 0.8 ms. Single photon emission computer tomography (SPECT) performed during phrenic nerve stimulation revealed focal neuronal activation in the somatosensory pathways. Intravenously administered Tc-99m Ethyl Cysteinnate Dimmer (ECD) was used as a blood flow tracer to obtain baseline and activated images. After image registration, baseline images were compared voxel-by-voxel with the activation images. The mean inter-subject summation image of the activated state was compared with that of the baseline state using ten normal subjects. The extent of the total voxel volume increase on the mean images of the 3 activated SPECT images was 0.7%, and a mean signal increase of 22%. For further anatomic localization of regional increases in signal, the magnetic resonance image (MRI) scan of each subject was registered and superimposed on the activated stage SPECT image. This method may be used clinically to study the pathophysiology of impaired central respiratory drive.
The English Rivermead Mobility Index (RMI) has been proposed as a simple, valid and reliable measure in stroke rehabilitation. A German version was established and validated in two centres. In centre ...A 46 acute (median: 3.0 days after onset) and in centre B 151 chronic (median: 88.0 days after onset) stroke patients participated. Interrater reliability of the German RMI was tested in 12 subjects in the acute stage of stroke and was found to be statistically significant (r = 0.98, P < 0.0001). In centre A, a statistically significant correlation was found between the German RMI and the 10‐m walk time at baseline (r = 0.73, P < 0.0001) and after three weeks (r = 0.92, P < 0.0001). In centre B, the German RMI correlated significantly with the motor part of the Functional Independence Measure (motor‐FIM) on admission (r = 0.78, P < 0.0001) and after three weeks (r = 0.79, P < 0.0001), respectively. The change of the RMI correlated significantly with the change in 10‐m walk time in acute patients (r = 0.87, P < 0.0001) and with the change in motor‐FIM in chronic patients (r = 0.54, P < 0.0001). A moderate ceiling‐effect was detected in the chronic study population. The German RMI appears to be a reliable, valid and responsive measure for mobility disability in acute and chronic stroke patients.
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