Diagnostic performance of four SARS-CoV-2 antibody assays in patients with COVID-19 or with bacterial and non-SARS-CoV-2 viral respiratory infections

European Journal of Clinical Microbiology & Infectious Diseases - SARS-CoV-2 antibody assays are used for epidemiological studies and for the assessment of vaccine responses in highly...     

Alteration in the response properties of primary somatosensory cortex related to differential aversive Pavlovian conditioning

The effects of differential aversive Pavlovian conditioning on the functional organization of primary somatosensory cortex (SI) were examined in 17 healthy participants. Neuroelectric source imaging from 60 electrodes was employed while nine subjects received an innocuous electric stimulus (conditioned stimulus, CS) to one finger (left or right) that was followed by painful electric shock to the lower back (unconditioned stimulus, US) and an innocuous stimulus to the other finger that was never followed by pain. Eight subjects received a presentation of the innocuous and painful stimuli with equal probability to both fingers (control group). The data included the electromyogram (EMG) from the left m. corrugator, and judgments of intensity, aversiveness, and CS-US contingency. Only the experimental group displayed EMG conditioning, differential contingency judgments, as well as a change of dipole orientation for the CS and an enhanced dipole moment for the US in the electroencephalogram. Intensity and unpleasantness ratings were altered in a more unspecific manner and did not differ between groups and stimulus conditions. The data suggest that SI contributes to memory processes in associative learning. Pavlovian conditioning of tactile responses might be important in the altered processing of painful stimuli in chronic pain patients where enhanced conditioning has been demonstrated.     

The importance of ‘awareness’ for understanding fetal pain

Our understanding of when the fetus can experience pain has been largely shaped by neuroanatomy. However, completion of the cortical nociceptive connections just after mid-gestation is only one part of the story. In addition to critically reviewing evidence for whether the fetus is ever awake or aware, and thus able to truly experience pain, we examine the role of endogenous neuroinhibitors, such as adenosine and pregnanolone, produced within the feto-placental unit that contribute to fetal sleep states, and thus mediate suppression of fetal awareness. The uncritical view that the nature of presumed fetal pain perception can be assessed by reference to the prematurely born infant is challenged. Rigorously controlled studies of invasive procedures and analgesia in the fetus are required to clarify the impact of fetal nociception on postnatal pain sensitivity and neural development, and the potential benefits or harm of using analgesia in this unique setting.     

Correction to: Diagnostic performance of four SARS-CoV-2 antibody assays in patients with COVID-19 or with bacterial and non-SARS-CoV-2 viral respiratory infections

European Journal of Clinical Microbiology & Infectious Diseases -     

Central processing of acute muscle pain in chronic low back pain patients: an EEG mapping study.

The presence of perceptual sensitization and related brain responses was examined in 14 chronic low back pain (CLBP) patients and 13 healthy controls comparable in age and sex. Multichannel EEG recordings and pain ratings were obtained during the presentation of 800 painful electrical intramuscular and intracutaneous stimuli each to the left m. erector spinae and the left m. extensor digitorum. Perception and pain thresholds were not significantly different between the two groups, though patients showed significantly more perceptual sensitization. Across all stimulation conditions, a larger EEG component 80 milliseconds after stimulation was observed in the CLBP group. No significant group differences were found for the N150. The component 260 milliseconds after stimulus onset was significantly smaller in the CLBP group. N80, N150, and perceptual sensitization were significantly positively correlated. These results indicate enhanced perceptual sensitization and enhanced processing of the sensory-discriminative aspect of pain, as expressed in the N80 component, in CLBP patients. This may be one neurophysiologic basis of sensitization and the chronicity process. The lower P260 component in the patients may be explained in terms of tonic pain inhibiting phasic pain or may be related to the affective distress observed in this patient group.     

Cardiac output by Portapres

Portapres derives continuous estimates of cardiac output from the peripheral pulse and has the potential to be an extremely valuable physiological and clinical tool. We assessed Portapres estimates of cardiac output in healthy subjects at rest, during maximal treadmill exercise ( n = 8) and during decreases caused by orthostatic stress ( n = 8). Comparison with a rebreathing method indicated that Portapres tended to overestimate cardiac output. The random errors of the estimates (precision), expressed as +/- 2 S.D. of the differences between paired estimates during steady states, ranged between 1.2 and 2.6 litres/min. We conclude that these errors indicate that the method is probably only useful for assessing changes in individual subjects where large changes are anticipated, as during exercise. When smaller changes occur, as during orthostasis, the errors preclude the use of individual subject data and only permit group average data to be examined.