„Rebound pain“ – von der Definition bis zur Therapie

Die Anaesthesiologie - Rebound pain als Nebenwirkung einer Regionalanästhesie ist ein übermäßiges Schmerzempfinden nach Abklingen der Wirkung der lokalen Betäubung, welches...     

Kinetic analysis of interactions between alkylene-linked bis-pyridiniumaldoximes and human acetylcholinesterases inhibited by various organophosphorus compounds

The therapeutic approach of organophosphorus compound (OP) intoxications is to reactivate the inhibited enzyme acetylcholinesterase (AChE). Numerous studies demonstrated a limited efficacy of standard oxime-based reactivators against different nerve agents such as tabun and cyclosarin. This emphasizes research for more effective oximes. In the present study, reactivation kinetics of tabun-, sarin-, cyclosarin-, VX- or paraoxon-ethyl-inhibited human AChE (hAChE) with a homologous series of bis-ortho-pyridiniumaldoximes, Ortho-4 - Ortho-9, was investigated with a robot-assisted setting, allowing determination of second-order reactivation rate constants as well as model calculations. The reactivation constants of Ortho-4 - Ortho-9 resulted in marked differences of affinity and reactivity depending on the OP structure and the linker length of the oximes. In general, the K_D values decreased with increasing linker length. Reactivity increased from Ortho-4 to Ortho-6 for PXE- and VX-inhibited hAChE and from Ortho-4 to Ortho-7 for GA-inhibited hAChE and decreased again with Ortho-8 and Ortho-9. In contrast, k_r decreased with increasing linker length for sarin- and cyclosarin-inhibited hAChE. In view of the pronounced decrease of K_D from Ortho-4 to Ortho-9, the k_r2 values increased with all tested OP. Hence, the ratios of K_I/K_D and of K_I/k_r2 showed that in almost all cases the affinity of Ortho-N to the native hAChE was higher than to OP-inhibited enzyme. Model calculations indicated that Ortho-6 - Ortho-9 could be superior to obidoxime in reactivating tabun-inhibited hAChE. Finally, these data emphasize the need to develop oximes with a higher selective affinity towards OP-inhibited hAChE in order to minimize possible side effects.     

Refractive surgery in anisometropic adult patients induce plastic changes in primary visual cortex

Purpose: To prospectively study the effect of refractive surgery in the primary visual cortex of adult anisometropic and isometropic myopic patients. Methods: Two anisometropic and two isometropic myopic patients were examined with multifocal functional magnetic resonance imaging technique (mffMRI) before refractive surgery and at 3, 6, 9 and 12 months postoperatively. Two controls without refractive surgery were also examined with mffMRI in the beginning and in the end of the study. Anisometropic patients had only their more myopic eye operated to correct the anisometropia. The myopic isometropic patients had their both eyes operated. Results: Operated anisometropic eyes showed 65% reduced amount of active voxels in foveal data at 12 months postoperatively compared with the preoperative situation. In unoperated anisometropic eyes, the corresponding value was 86% and in myopic patients and controls 31% and 1%, respectively. To confirm this finding, the number of activated voxels representing the innermost ring of the stimulus was also calculated, and an exactly similar phenomenon was encountered in the anisometropic patients. Both anisometropic patients improved the best‐spectacle‐corrected visual acuity in the operated eye after refractive surgery. Conclusion: Our results suggest that plastic changes may take place in the primary visual cortex of anisometropic adult patients after refractive surgery.     

Pathomechanisms and treatment of pediatric aneurysms

Pediatric aneurysms are rare diseases distinct from classical adult aneurysms and therefore require different treatment strategies. Apart from saccular aneurysms that are more commonly found in older children, three major pathomechanisms may be encountered: trauma, infection, and dissection. The posterior circulation and more distal locations are more commonly encountered in children compared to adults, and there is an overall male predominance. Clinical findings are not only confined to subarachnoid hemorrhage but may also comprise mass effects, headaches or neurological deficits. In traumatic aneurysms, the skull base and distal anterior communicating artery are commonly affected, and the hemorrhage occurs often delayed (2–4 weeks following the initial trauma). Infectious aneurysms are mostly bacterial in origin, and hemorrhage occurs early after a septic embolic shower. Dissecting aneurysms are the most often encountered aneurysm type in children and can lead to mass effect, hemorrhage, or ischemia depending on the fate of the intramural hematoma. Treatment strategies in pediatric aneurysms include endosaccular coil treatment only for the “classical berry-type” aneurysms; in the other instances, parent vessel occlusion, flow reversal, surgical options, or a combined treatment with bypass and parent vessel occlusion have to be contemplated.     

Heterogeneity of congnitive profiles in aging: successful aging, normal aging, and individuals at risks for cognitive decline

Neuropsychological clinical decision-making is complicated by the fact that variability in test performance increases with advancing age. This research explores the presence of homogeneous subgroups in 120 neurologically healthy individuals, from 55 to 85 years of age. Subjects at risk for dementing diseases were diagnosed as Aging-Associated Cognitive Decline (AACD) and Mild Cognitive Impairment (MCI). Cluster analysis was applied on 11 neuropsychological variables assessing logical memory immediate recall and retention percentage, visual memory immediate recall and retention, conceptual thinking, naming, verbal fluency, constructional functions, motor speed, flexibility and finger tapping. Five clusters were extracted, one representing cognitively successfully aged, and two consisting of individuals with normal or average level of performance. One cluster was characterized by older subjects with difficulties in visual memory, visuoconstructional functions, and speed and attention, most of the younger subjects in the same cluster had a diagnosis of AACD or MCI. The fifth cluster represented individuals at risk for dementing diseases; most of them were diagnosed having AACD and more than half had a diagnosis of MCI. Age, activity and intellectual levels, and to a lesser degree education, were significantly related to the cluster solution. The present findings caution against treating samples of elderly individuals as homogeneous.     

Perceived functional disabilities among rheumatoid arthritis patients

The aim of this study was to determine from patient perspective the most relevant physical functions when estimating the functional disabilities, and to estimate the perceived relative influence of them. Structured telephone interviews were conducted among 143 RA patients. The subjects were asked to name functions and activities in their everyday life, which were affected by RA. After this, they were asked to score each of the named item with a scale from 0 to 100. These were combined with earlier collected data on sociodemographic background and clinical status. Listed activities were grouped to functional disabilities and further categorized according to joints, limbs and body areas. One or more functional disabilities affecting everyday life because of RA was mentioned by 87.4%, altogether 354 mentions. The most commonly mentioned disabilities were walking and opening jars. However, the most commonly mentioned disabilities were not those with highest perceived disabilities. Of the 59 different types of disabilities mentioned, 25 were connected with movements of the shoulder, 30 with elbow, 40 with wrist, and 37 with fingers. Movements of the back were involved in 20 mentioned disabilities, hip and knee both in 8, and ankles in 6. Disabilities related to lower extremity functions were considered most disabling. In conclusion, to describe RA patients’ functional disability, the measured functions should be those which the patients themselves consider relevant and causing disability. Furthermore, the studied functional measures ought to be weighted according to the relative influence of each function to the patients.