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Biomedical subjects

M Härle

Publications and source records attributed to M Härle.

18 recordsLinked to original sources
PubMed2001

Walking or talking? Behavioral and neurophysiological correlates of action verb processing.

Brain activity elicited by visually presented words was investigated using behavioral measures and current source densities calculated from high-resolution EEG recordings. Verbs referring to actions usually performed with different body parts were compared. Behavioral data indicated faster processing of verbs referring to actions performed with the face muscles and articulators (face-related words) compared to verbs referring to movements involving the lower half of the body (leg-related words). Significant topographical differences in brain activity elicited by verb types were found starting approximately 250 ms after word onset. Differences were seen at recording sites located over the motor strip and adjacent frontal cortex. At the vertex, close to the cortical representation of the leg, leg-related verbs (for example, to walk) produced strongest in-going currents, whereas for face-related verbs (for example, to talk) the most in-going activity was seen at more lateral electrodes placed over the left Sylvian fissure, close to the representation of the articulators. Thus, action words caused differential activation along the motor strip, with strongest in-going activity occurring close to the cortical representation of the body parts primarily used for carrying out the actions the verbs refer to. Topographically specific physiological signs of word processing started earlier for face-related words and lasted longer for verbs referring to leg movements. We conclude that verb types can differ in their processing speed and can elicit neurophysiological activity with different cortical topographies. These behavioral and physiological differences can be related to cognitive processes, in particular to lexical semantic access. Our results are consistent with associative theories postulating that words are organized in the brain as distributed cell assemblies whose cortical distributions reflect the words' meanings.

Adolescent↗
PubMed2001

Syntactic and semantic processing in the healthy and aphasic human brain.

A syntactic and a semantic task were performed by German-speaking healthy subjects and aphasics with lesions in the dominant left hemisphere. In both tasks, pictures of objects were presented that had to be classified by pressing buttons. The classification was into grammatical gender in the syntactic task (masculine or feminine gender?) and into semantic category in the semantic task (man- or nature made?). Behavioral data revealed a significant Group by Task interaction, with aphasics showing most pronounced problems with syntax. Brain event-related potentials 300-600 ms following picture onset showed different task-dependent laterality patterns in the two groups. In controls, the syntax task induced a left-lateralized negative ERP, whereas the semantic task produced more symmetric responses over the hemispheres. The opposite was the case in the patients, where, paradoxically, stronger laterality of physiological brain responses emerged in the semantic task than in the syntactic task. We interpret these data based on neuro-psycholinguistic models of word processing and current theories about the roles of the hemispheres in language recovery.

Adult↗
PubMed2000

Neurophysiological distinction of verb categories.

Neurophysiological brain responses to subcategories of action verbs were recorded using high resolution EEG. Starting 240 ms after word onset, topographies of event-related potentials distinguished between verbs referring to different action types. Current source density estimates revealed that verbs referring to actions executed with the legs (to kick) produced an activity focus close to the vertex, above motor areas involved in the programming of leg movements, whereas face-related verbs (to speak) produced a focus at left-lateral recordings, above perisylvian areas and the cortical representation of the face and articulators. This is evidence that brain mechanisms involved in word processing can differ even between fine-grained lexico-semantic subcategories and already within the first quarter of a second after word onset. We offer an explanation of the data in neurobiological terms.

Adult↗
PubMed1998

Fibrin sealing in peptic ulcer bleeding: the fate of the clot.

BACKGROUND AND STUDY AIMS: The injection of fibrin tissue glue is a promising endoscopic method for hemostasis of peptic ulcer bleeding. So far, no clinical study has focused on the ulcer healing process after endoscopic fibrin injection. PATIENTS AND METHODS: A morphological study was performed on all resection specimens from patients operated on between 1 January 1994 and 31 December 1996 for gastroduodenal ulcer bleeding with prior endoscopic injection of fibrin glue. The fibrin clot was characterized histologically for its size, location and aspect. RESULTS: Of 227 patients endoscopically treated with a double-lumen needle, 20 underwent resection. The interval between fibrin injection and resection ranged from 6 hours to 9 days. In 15 patients the ulcer was identified in the resection specimen. No fibrin remnants were detectable in three, sparse fibrin deposits were seen in eight and large amounts of fibrin were noted in the submucosa or subserosa in four specimens. With increasing time, the clot was gradually organized by phagocytes and angio-fibroblasts and was finally replaced by endogenous granulation tissue. An exuberant or tissue-destructive reaction did not appear. CONCLUSIONS: In this study, endoscopic fibrin sealing of bleeding ulcers resulted in appearance of a bland fibroblast-rich granulation tissue. The depth of fibrin glue injection is difficult to standardize with the aid of double-lumen needles.

Duodenum↗
PubMed1996

Cystic endometriosis of the upper abdominal organs. Report on three cases and review of the literature.

A 34-year-old woman with signs and symptoms of an acute abdomen was found to have a hepatic cyst on NMR- and CT-scan. With the tentative diagnosis of a liver hematoma, a right hemihepatectomy was performed. Histologically, an endometrial cyst of the liver was found. A second case of cystic endometriosis in the liver was revealed ultrasonographically in a 62-year-old woman, complaining of rightsided epigastrical pain. A 28-year-old woman was admitted to the hospital because of recurrent epigastric pain. A cystic tumor of the pancreas could be visualized ultrasonographically and was interpreted as a postinflammatory pseudocyst. Histological examination of the distal pancreatectomy specimen revealed cystic endometriosis. The clinicopathological features of hepatic and pancreatic endometriosis are discussed and the literature concerning these extremely rare lesions is reviewed.

Adult↗
PubMed1996

Centromere and telomere movements during early meiotic prophase of mouse and man are associated with the onset of chromosome pairing.

The preconditions and early steps of meiotic chromosome pairing were studied by fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes to mouse and human testis tissue sections. Premeiotic pairing of homologous chromosomes was not detected in spermatogonia of the two species. FISH with centromere- and telomere-specific DNA probes in combination with immunostaining (IS) of synaptonemal complex (SC) proteins to testis sections of prepuberal mice at days 4-12 post partum was performed to study sequentially the meiotic pairing process. Movements of centromeres and then telomeres to the nuclear envelope, and of telomeres along the nuclear envelope leading to the formation of a chromosomal bouquet were detected during mouse prophase. At the bouquet stage, pairing of a mouse chromosome-8-specific probe was observed. SC-IS and simultaneous telomere FISH revealed that axial element proteins appear as large aggregates in mouse meiocytes when telomeres are attached to the nuclear envelope. Axial element formation initiates during tight telomere clustering and transverse filament-IS indicated the initiation of synapsis during this stage. Comparison of telomere and centromere distribution patterns of mouse and human meiocytes revealed movements of centromeres and then telomeres to the nuclear envelope and subsequent bouquet formation as conserved motifs of the pairing process. Chromosome painting in human spermatogonia revealed compacted, largely mutually exclusive chromosome territories. The territories developed into long, thin threads at the onset of meiotic prophase. Based on these results a unified model of the pairing process is proposed.

Animals↗
PubMed1996

Comparative genomic hybridization (CGH) discloses chromosomal and subchromosomal copy number changes in Merkel cell carcinomas.

We analyzed three Merkel cell carcinomas (MCC), applying comparative genomic hybridization (CGH) with DNA from paraffin-embedded and cultured tumor material as the probes. By this method, numerous changes in chromosome copy numbers were observed in each tumor investigated. Recurrent gains of chromosomes 1, 6, 18q and 20 were detected in two tumors. A third tumor showed complex chromosomal copy number changes, including gain of chromosome 8 and 9. These gains, as well as gain of chromosome 1 in the first two tumors, were confirmed by fluorescence in situ hybridization to paraffin tissue sections. Our results support the view that important genes for MCC development may be located on chromosomes 1, 6, 18q and 20.

Aged↗
PubMed1996

[5-fluorouracil: cause of a fatal myocardial infarction in combined radiochemotherapy?].

PURPOSE: A 53-year-old female patient was treated with combined radiochemotherapy with 5-fluorouracil (5-FU) because of adenocarcinoma of the lung. She died after the 2nd day of the first course on fatal myocardial infarction. The histological evaluation of the heart revealed no severe chronic fibrosis. In our opinion the myocardial infarction was partly 5-fluorouracil-related in this case. PATIENTS AND METHODS: Published case reports on this theme were reviewed and discussed. RESULTS: The review of the literature showed a 5-FU associated cardiotoxicity in 98 cases. Most of the patients were without evidence of pre-existing myocardial disorders. The discussion about the reasons of the 5-FU-associated cardiotoxicity is still going on. Cardiotoxicity will rise up in 1.1% to 4.5% of the patients treated with 5-FU. Patients with a history of cardiac disease were at significantly increased risk for 5-FU-induced cardiotoxicity. CONCLUSION: In high-risk-patients 5-FU should not be given without electrocardiographic monitoring. The continuous infusion is better than a bolus treatment.

Adenocarcinoma↗
PubMed1995

Analysis of sex chromosome distribution in the gonadal tissue of a 45,X/47,XYY mosaic by fluorescence in situ hybridization.

45,X/47,XYY mosaicism is a rare condition with scarce information on the tissue-specific distribution of the different cell lines. Fluorescence in situ hybridization with repetitive, chromosome-specific DNA probes was applied to gain insight into the tissue-specific distribution of the two cell lines in biopsies of the streak gonad and dysgenetic testis of a 2-year-old individual exhibiting 45,X/47,XYY mosaicism. The distribution of the 45,X/47,XYY cells within different tissues was found to be nonrandom. The coelomic epithelium, the vascular endothelium, and the prepuberal germ cells exhibited predominantly a 47,XYY karyotype. In contrast, Sertoli cells exhibited both karyotypes, and the remaining tissue was predominantly composed of 45,X cells. The contribution of the two cell lines to gonadal development is discussed.

Child, Preschool↗
PubMed1994

Human glomerular mesangial cells express CD16 and may be stimulated via this receptor.

CD16, a low affinity receptor for IgG, was found on cultured human glomerular mesangial cells (GMC) by Western blot analysis, cell ELISA and in situ hybridization. To characterize the molecule in more detail, reverse polymerase chain reaction was performed and the PCR products were analyzed. From sequence analysis and from hybridization experiments with oligonucleotides specific for either the transmembrane form or the glycosylphosphatidylinositol anchored form it was found that GMC-CD16 was similar to NK-CD16. This indicates that GMC express the transmembrane form of CD16. Comparison between nonstimulated GMC and GMC stimulated by aggregated gammaglobulin revealed no qualitative or quantitative difference in the expression of CD16. Incubation of GMC with aggregated gammaglobulin or with monoclonal antibodies to CD16 was followed by a time and dose dependent release of interleukin-6, suggesting that signals were transmitted by CD16. The occupancy of CD16 by immune complexes that may be deposited in various forms of glomerulonephritis might contribute to the perpetuation of inflammatory processes in the kidney.

Amino Acid Sequence↗
PubMed1992

Magnetic resonance imaging follow-up in Creutzfeldt-Jakob disease.

The history of a 67-year-old woman with histologically proven Creutzfeldt-Jakob disease (CJD) is presented. Before typical clinical and neurophysiological signs of CJD developed, magnetic resonance imaging (MRI) showed slightly enhanced signal intensity of the caudate nuclei and putamina in T2-weighted and proton density images, corresponding to spongiform degeneration in neuropathological examination. Five weeks later characteristical progressive cortical atrophy was demonstrated by follow-up MRI.

Aged↗
PubMed1987

[Cervical radiation myelopathy with spastic paraparesis of the arms. Case report and a review of the literature].

A case of cervical radiation myelopathy following telecobalt-radiation therapy to the cervical lymph-nodes in Hodgkin's disease is described. After a latent period of 3 months neurological symptoms presented with a pure spastic paraparesis of the upper extremities. Diagnosis was confirmed neuropathologically. A review is given on clinical signs of cervical radiation myelopathy.

Aged↗
PubMedDate not supplied

Childhood progressive spinal muscular atrophy with facioscapulo-humeral predominance, sensory and autonomic involvement and optic atrophy.

A female child of healthy parents developed rotary nystagmus at the age of 15 months. Ophthalmoscopy disclosed incomplete optic atrophy. Blood tests, EEG and CT scans were normal. At 20 months progressive muscular weakness and wasting with limb-girdle distribution commenced, followed later by disturbance of gait. From muscle and nerve biopsy the diagnosis of a peripheral neuropathy with neurogenic muscular atrophy was made. No mental change occurred. At 23 months she sustained cardiac arrest and was resuscitated; thereafter, she remained in a vegetative state and expired 9 months later. Her brain was markedly atrophic and firm. Diffuse old ischemic necroses and neuronal loss with gliosis were found in the cortex, the neostriatum, the thalamus, parts of the lower brainstem, and the cerebellum. Her optic nerves and tracts showed complete atrophy. The spinal cord exhibited degeneration and loss of motor neurons with cervical accentuation. The intermediolateral nuclei, the dorsal nuclei and the spinal ganglia were also involved. There was demyelination of the posterior funiculi, the pyramidal tracts, and the sciatic, peroneal, sural, and superior frontal nerve. The voluntary muscles exhibited large group atrophy with liposclerotic change and limb-girdle predominance. The neck, tongue and ocular muscles were also involved, as were, to a less extent, the lower limbs. Although the loss of motor neurons in the spinal cord and at the bulbar level with the typical pattern of neurogenic muscular atrophy, as well as its distribution, resemble the facioscapulo-humoral type of heredity motor neuropathy (HMN), early onset, rapid course, sensory and autonomic involvement, and atrophy of the optic nerve do not fit this or any one type of HMN.

Atrophy↗