Evidence of cortical learning in vegetative state.
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Acoustic Stimulation↗
Biomedical subjects
A Semmler
Publications and source records attributed to A Semmler.
Methionine metabolism and phenotypic variability in X-linked adrenoleukodystrophy.
A combined genotype of polymorphisms of methionine metabolism has been associated with CNS demyelination in methotrexate-treated patients. Within a sample of 86 patients with X-linked adrenoleukodystrophy, this genotype was overrepresented in a subgroup of 15 patients with adrenomyeloneuropathy (AMN) with CNS demyelination (adrenoleukomyeloneuropathy) in comparison to 49 AMN patients without CNS demyelination ("pure" AMN; p = 0.002), suggesting that methionine metabolism might contribute to the phenotypic variability in adrenoleukodystrophy.
Adolescent↗
Information processing in severe disorders of consciousness: vegetative state and minimally conscious state.
OBJECTIVE: To study the presence of electrophysiological indicators of remaining cortical functions in patients with persistent vegetative state (PVS) and minimally conscious state (MCS). Previous electrophysiological and PET data indicated that some PVS patients have partially intact cortical processing functions. However, it remains unclear whether the reported patients were representative for PVS population or just some exceptional cases. METHODS: Event-related brain responses to stimuli of different complexity levels, recorded in 98 patients with extremely severe diffuse brain injuries, 50 of which in PVS. Four main indicators of cortical functions were: (i) N1-P2 complex as an index of simple, undifferentiated cortical processing; (ii) mismatch negativity as an index of pre-attentive, probably unconscious, cortical orientation; (iii) P3 wave as an index of deep cortical analysis of physical stimuli, and (iv) brain responses to semantic stimuli. RESULTS: Cortical responses were found in all PVS patients with a background EEG activity > 4 Hz. All responses investigated, including those to semantic stimuli that indicated comprehension of meaning, occurred significantly above chance, though less frequently than in patients with severe brain injuries who were conscious. CONCLUSIONS: Cortical responses were lacking in most patients with severe EEG slowing (< 4 Hz). Follow-up data revealed that the presence of a mismatch negativity, a short disease duration, and the traumatic etiology were related to a better outcome. SIGNIFICANCE: The data show that in a subpopulation of PVS patients with preserved thalamocortical feedback connections, remaining cortical information processing is a consistent finding and may even involve semantic levels of processing.
Auditory Cortex↗
Giant cell arteritis causing multiple vertebro-basilar infarcts.
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Aged↗
Surface Properties of Alkylpyridinium Chlorides and the Applicability of the Pendant Drop Technique.
Measurement of interfacial tension isotherms and critical micelle concentrations (CMCs) of surfactant solutions is of major concern in surface science. In this study we investigate the group of cationic alkylpyridinium surfactants. Despite widespread applications, their physicochemical properties (especially tetra- and octadecylpyridinium chloride) are not so well characterized. The surface tension isotherms of 12 different surfactant/water/KCl systems are systematically determined by means of a new laser tensiometer (LASDA) with the pendant drop technique. The surfactants are purified using the Lunkenheimer method, which is capable of providing surfactants of high purity. From surface tension isotherms, values for excess concentrations, cross-sectional areas, and CMCs are obtained. The long-chain surfactants, especially octadecylpyridinium chloride, show some strange behavior, which is probably due to slow transport processes. We discuss in some detail diffusion limitations of the pendant drop technique that can drastically increase the time until equilibrium surface tension is reached, especially in the case of highly surface-active substances. Copyright 1999 Academic Press.
Journal Article↗
[A case report of malignant hyperthermia in a 14-month-old boy].
A 14-month-old boy underwent bilateral antrotomies and adenotomy for bilateral mastoiditis. During the operation, typical symptoms of malignant hyperthermia (MH) became apparent. At the time of operation, pulse oximetry and capnometry were not possible which led to a delay in making the diagnosis. Nevertheless, Dantrolene, which was available in the operating theatre, was immediately administered. The postoperative recovery was complicated by altered cerebral function (inability to concentrate), muscle exhaustion and a coagulopathy which lasted for eleven days. A muscle biopsy of the child's father was positive for MH.
Dantrolene↗