Object-motion detection affected by concurrent self-motion perception: psychophysics of a new phenomenon

Thresholds for object-motion detection are significantly raised when concurrent self-motion perception is induced by either vestibular, or visual, or cervico-somatosensory stimulation. Active sinusoidal horizontal head oscillations with compensatory vestibulo-ocular reflex (VOR) and foveal or eccentrical target presentation; 'passive' head movements with fixation suppression of the VOR; pure body oscillations with the head fixed in space (cervical stimulation); optokinetically induced apparent self-motion (circularvection). This new visual phenomenon of a physiological 'inhibitory interaction' between object- and self-motion perception seems to have a somatosensory motor analogue. It may reflect the disadventageous side effect due to unspecificness of an otherwise beneficial space constancy mechanism, which provides us with the image of a stable world during locomotion.     

Neuropathological aspects of Alzheimer disease

In the present review we describe the morphological features of Alzheimer's disease (AD) and compare these findings with those obtained in argyrophilic grain disease, a frequent but often unrecognized form of late-onset dementia. Macroscopically AD brains exhibit a marked atrophy of the medical temporal lobe, including the hippocampus, entorhinal cortex and amygdala. Neuronal loss, decreased synapse density and the intra- and extracellular deposition of abnormal proteins constitute the histological hallmark lesions of AD. The intraneural accumulation of the microtubule-associated protein tau in a hyperphosphorylated state leads to the formation of neurofibrillary lesions (NFL). Whereas the widespread distribution of NFL in the neocortex correlates with the cognitive decline in AD patients no such correlation could be found for the extracellular deposition of the A beta-protein in the shape of senile plaques (SP). However, dementia correlates with the amount of neuritic degeneration within a subtype of SP ('neuritic plaques'). We further discuss some of the risk factors for AD, i.e. the genetic risk factors.     

Myocardial revascularization in threatening extension of myocardial infarction (author's transl)]

Myocardial revascularization was performed in 13 patients between two and 14 days following initial infarction because of impending re-infarction. The diagnosis of impending re-infarction was made on the basis of the following criteria: myocardial infarction; repeated stenocardia despite medical treatment; renewed ST-T changes in the ECG. The intra-aortic balloon pump was installed in 7 patients for haemodynamic reasons (shock, massively raised pressure in the pulmonary artery). 12 patients survived the surgical intervention and were eventually discharged free of stenocardia. The presented findings suggest that surgical intervention in impending re-infarction appears of value in those cases which have not been satisfactorily controlled by conventional medical treatment.     

Appropriate use of total parenteral nutrition in children with perforated appendicitis

Background

Total parenteral nutrition (TPN) is often used in children with perforated appendicitis, despite the absence of clear indications. We assessed the validity of specific clinical indications for initiation of TPN in this patient cohort.