Fixation instability and oculomotor abnormalities in Friedreich's ataxia

Eye movements were studied in 13 patients with Friedreich's ataxia and correlated with MRI findings to investigate whether oculomotor abnormalities can be traced to cerebellar disturbances in this disease. One of the most prominent eye signs was fixation instability (square-wave jerks, SWJ.). Besides SWJ the patients showed various combinations of cerebellar, vestibular and brain-stem oculomotor signs. Our patients did not comprise a homogeneous group with regard to their oculomotor findings. There was no correlation between the severity of any of the so-called cerebellar oculomotor disturbances and the number of SWJ. We tried to correlate the extent of oculomotor disturbances with floccular atrophy and atrophy of the dorsal vermis on MRI in seven of the patients. None of the oculomotor features (including SWJ) correlated with flocculus or dorsal vermis size. Furthermore, floccular and vermal measurements on MRI were normal. Accordingly, we think it unlikely that the oculomotor disturbances, including SWJ, are attributable to cerebellar pathology per se.     

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.     

Abnormalities of somatosensory evoked potentials in the quinolinic acid model of Huntington's disease: evidence that basal ganglia modulate sensory cortical input.

Intrastriatal injection of quinolinic acid (QA) in rats provides an animal model that mimics some of the neuropathological and neurochemical alterations observed in the striatum of patients with Huntington's disease (HD). One of the very early neurophysiological signs in HD is a diminution of amplitude of early somatosensory evoked potentials (SEPs) recorded over the parietal cortex. The present study investigated whether the QA model exhibits similar neurophysiological abnormalities. Two weeks after unilateral intrastriatal injection of QA (240 nmol) or of the solvent, early SEPs were recorded with chronically implanted electrodes from the somatosensory cortex or from the ventrobasal nucleus of the thalamus of lightly pentobarbital-anesthetized rats, in response to single-shock electrical stimulation of the contralateral forepaw. Whereas intrastriatal injection of solvent did not influence SEPs, the striatal QA lesion significantly reduced the amplitude of early cortical SEPs by about 40% without affecting the latency. SEPs recorded from the ventrobasal nucleus were unchanged after QA lesion. Histological examination and glial fibrillary acid protein staining after intrastriatal injection of QA revealed no evidence for damage in the somatosensory system. It is concluded that (1) the QA animal model of HD mimics some of the SEP abnormalities of patients, and (2) a striatal lesion modulates somatosensory transmission to the cortex in rats.     

Acute therapy of ischemic cerebral infarct

The ischaemic cerebral attack is a disease prevailingly of older age. Its prognosis is distinguished by a mortality rate as high as ever. From 1975 to 1985, 520 patients with ischaemic cerebral attack have been treated in hospital, with specific acute therapy changing from the so-called vasodilator therapy via osmotherapy into haemodilution therapy with lowmolecular dextrane. Since during vasodilator therapy any early mobilisation nor continuous physiotherapy were carried out and the patients prevailingly died of bronchopneumonia, the significantly lower mortality rate under osmotherapy and haemodilution therapy cannot be attributed to the specific drug therapy. In all probability it is a result of the improvement of care and of the active early mobilisation of the patients.     

Rolle der Winkelstabilität bei der intramedullären Stabilisierung

Zusammenfassung Winkelstabile Plattenfixateur-interne-Systeme haben in den letzten 20 Jahren zunehmend an Bedeutung gewonnen. Die aus der Winkelstabilität resultierende flächenhafte Krafteinleitung und gleichmäßigere Kraftverteilung führen zu einer besseren Knochenbruchheilung insbesondere im metaphysischen Bereich und bei Osteoporose. Bei Marknagelsystemen ist die Winkelstabilität bislang nur partiell verwirklicht. Der vorgestellte winkelstabile Tibiamarknagel realisiert an jedem einzelnen Bolzen eine Winkelstabilität mit dem einliegenden intramedullären Kraftträger. Von Februar 2002–August 2004 wurden 21 Patienten mit ihm behandelt. In 13 Fällen wurden Frakturen stabilisiert, 6 Patienten hatten Fehlstellungen, 2 Patienten Pseudarthrosen. Zum Nachuntersuchungszeitpunkt waren alle Behandlungen abgeschlossen. Postoperative Komplikationen traten nicht auf. In allen Fällen wurde eine vollständige Durchbauung erreicht. In 6 Fällen fand sich radiologisch eine verzögerte Knochenbruchheilung. Die ersten klinischen Erfahrungen mit dem winkelstabilen Tibiamarknagel zeigen, dass dieser aufgrund der höheren Primärstabilität insbesondere im metaphysären Knochenbereich mit kurzen Fragmenten sowie bei Osteoporose Vorteile gegenüber anderen nichtwinkelstabilen oder nur partiell winkelstabilen Marknagelsystemen erbringt. Die verzögerten Knochenbruchheilungen bedürfen weiterer klinischer und biomechanischer Untersuchungen.     

Akromioklavikulargelenkverletzungen

There is some controversy over the treatment of acromioclavicular injuries. The use of the Rockwood classification as the basis for decisions on whether operative or nonoperative treatment is indicated is discussed critically, and the authors' preferred operative technique is described and illustrated by examples. We treat injuries classified according to the Rockwood classification as types I and II with conservative methods. In type III injuries the patient's age, job and free time activities determine whether or not surgery is indicated. In the case of type IV or type VI injuries we always perform temporary internal fixation of the acromioclavicular joint, using transarticular K-wire fixation or hookplate osteosynthesis. Satisfactory results of both operative and nonoperative treatment are reported in the literature. The authors' own results are presented.     

Dependence and cross-dependence in the guinea-pig myenteric plexus

Summary Chronic activation of opioid receptors results in the development of tolerance and dependence. Tolerance may be confined to a single receptor type and thus has been termed selective tolerance. The present investigation reveals that prolonged activation of an inhibitory acting receptor type not only results in dependence associated with this receptor but also brings about cross-dependence. Cross-dependence involves both opioid receptors as well as non-opioid receptors, e. g. adrenoceptors. The experimental design employed did not permit conclusions to be drawn about whether those receptors exhibiting cross-dependence also developed tolerance. Regardless of the receptors and their specific subsequent transduction systems, all the receptors which showed dependence and cross-dependence proved sensitive to pertussis toxin, suggesting a critical function of GTP-binding proteins for the development of not only opioid dependence but also for drug dependence in general. Since multiple transmitter receptors may converge on the same ion channel, the concept of convergent dependences may be linked to GTP-binding proteins. However, no conclusions can be drawn with regard to the precise biochemical mechanisms underlying dependence. Send offprint requests to R. Schulz at the above address