Biomedical subjects

S Braeutigam

Publications and source records attributed to S Braeutigam.

5 recordsLinked to original sources

PubMed2006

[Molecular genetic and histopathological examinations for genotype-phenotype analysis in patients with TGFBI-linked corneal dystrophy].

PURPOSE: Different missense mutations in the TGFBI gene cause granular (Groenouw CDGG1, Avellino CDA, Reis-Bücklers CDB1) and lattice (Type I; Biber-Haab-Dimmer; CDL1) corneal dystrophies and, in some reports, corneal dystrophy Thiel-Behnke (CDB2). We report on the mutation spectrum and the genotype-phenotype correlations on the basis of clinical and histopathological examinations of 13 German families with TGFBI-linked corneal dystrophies. METHODS: In 31 patients with different corneal dystrophies, DNA was extracted from leukocytes of the peripheral blood and mutation analysis was performed by direct sequencing of the TGFBI gene. Clinical and histopathological findings were compared with the molecular genetic findings for genotype-phenotype correlations. RESULTS: In 6 patients (2 families/one single person) with clinical and histopathological CDL1 we found a Missense mutation Arg124Cys and in 7 patients (3 families/one single person) with clinical and histopathological CDA we found a Missense mutation Arg124His in the exon 4 of the TGFBI gene. In 12 patients (4 families/2 single persons) with clinical and histopathological CDGG1 we found a Missense mutation Arg555Trypt in the codon 12 of the TGFBI gene. In all five patients (1 family/4 single persons) with clinical and histopathological CDB2 we could not find any mutation in the TGFBI gene. In one patient with exceptional clinical and histopathological findings we found a Missense mutation Ala546Asp, which was reported before only twice in connection with polymorphous corneal amyloidosis. CONCLUSIONS: In comparison of our clinical and histopathological findings and the molecular genetic results we found a strong genotype-phenotype correlation in patients with TGFBI-linked corneal dystrophies. Rare mutations can lead to exceptional clinical and histopathological findings which cannot be classified into the different groups of corneal dystrophies. In our patients with CDB2 we could not find any molecular genetic correlation to the TGFBI gene.

Adult↗

PubMed2001

Task-dependent early latency (30-60 ms) visual processing of human faces and other objects.

Electrophysiological responses to previously seen faces reportedly differ from those to novel faces at shorter latencies than generally associated with complex visual analysis. It is unclear, however, whether such observations are unique to faces, and which stages of visual processing they reflect. MEG was used in 21 normal adults to record neural responses to images of faces, other objects and abstract patterns presented individually as part of a classification task and in sequential pairs as part of an image comparison task. The amplitudes of the short latency responses (30-60 ms) to the first image in pairs of faces were significantly greater than the responses to both the second faces and the individual face images. These early responses were recorded over predominantly right hemisphere parietal and occipito-temporal cortical regions including areas that, at longer latencies, have been associated with face specific activity. The differences in the responses within pairs were less for non-face objects and absent for abstract geometrical patterns. No early neuronal activity was observed in the classification task. The results indicate the existence of early latency neural networks that are sensitive to both stimulus type and task and are strongly activated by faces.

Adult↗

PubMed2001

Phase-locked gamma band responses to semantic violation stimuli.

This paper addresses the role of gamma-band activity in semantic networks associated with the processing of words and sentences in humans. Magnetoencephalography (MEG) was used to compare the responses of eleven normal volunteers to semantically congruous and incongruous words at the end of syntactically correct sentences. The averaged low frequency responses evoked by the two word classes were clearly different within the latency range associated with N400 components. The oscillatory characteristics of the evoked responses were analysed using Gabor transform techniques in conjunction with statistical re-sampling. This revealed transient gamma-oscillations ( approximately 35 Hz) that were significantly phase-locked to both types of stimuli but preferentially present at intermediate ( approximately 300 ms) and long (>500 ms) latencies for incongruous words. This stimulus dependent phase locked gamma-activity occurred at latencies that were distinct from the short latency and evoked N400 components. The findings suggest that synchronised oscillations provide independent information about brain dynamics and that some semantic processes may dissociate into distinct functional stages.

Adult↗

PubMed2001

Magnetoencephalographic signals identify stages in real-life decision processes.

We used magnetoencephalography (MEG) to study the dynamics of neural responses in eight subjects engaged in shopping for day-to-day items from supermarket shelves. This behavior not only has personal and economic importance but also provides an example of an experience that is both personal and shared between individuals. The shopping experience enables the exploration of neural mechanisms underlying choice based on complex memories. Choosing among different brands of closely related products activated a robust sequence of signals within the first second after the presentation of the choice images. This sequence engaged first the visual cortex (80-100 ms), then as the images were analyzed, predominantly the left temporal regions (310-340 ms). At longer latency, characteristic neural activation was found in motor speech areas (500-520 ms) for images requiring low salience choices with respect to previous (brand) memory, and in right parietal cortex for high salience choices (850-920 ms). We argue that the neural processes associated with the particular brand-choice stimulus can be separated into identifiable stages through observation of MEG responses and knowledge of functional anatomy.

Adult↗

PubMed1999

Field intercomparison of diffusive samplers for measuring ammonia.

Agricultural production systems are recognised as a major source of atmospheric ammonia. Deposition of ammonia and ammonium may contribute to undesired changes in oligotrophic ecosystems. The continuous measurement of atmospheric ammonia requires expensive and sophisticated techniques and is performed only in a very restrict number of ambient air stations in Europe. Therefore, the application of passive samplers, which have the advantage of being easy to handle and cost-efficient, is useful. In the past the comparability of different passive samplers must be considered as rather scarce. In a joint European project under the leadership of the GSF-Forschungszentrum für Umwelt und Gesundheit, Neuherberg, in 1997 a comparison of different passive ammonia monitoring methods was carried out in a prealpine rural site near Garmisch-Partenkirchen. It was considered valuable to include not only well established systems but also methods still being developed. For the comparative test ten working groups with different methods took part. A wet annular denuder system, which has been developed by the Netherlands Energy Research Foundation for on-line measurement of atmospheric ammonia, served as reference of passive methods. The experiment, which started in June and finished in December, showed that most of the passive samplers fulfil the requirements and can be recommended for further measurements. Additional measurements of meteorological parameters were performed to check the influences of different weather conditions on passive sampling.

Agriculture↗