Evaluation of sympathetic blockade after intrathecal and epidural lidocaine in rats by laser Doppler perfusion imaging

The widespread use of neuraxial anaesthesia increases the need for animal models to evaluate therapeutic prospects, mechanisms and risks of this technique. As a methodological prerequisite, we characterised the sympathetic blockade after different modes of neuraxial anaesthesia with regard to segments supplying the splanchnic region. Under haemodynamic monitoring, lidocaine 2% or saline were infused via intrathecal (10 microl), lumbar epidural (10 and 30 microl) or thoracic epidural (10 and 30 microl) catheters. Segmental spread of neuraxially infused local anaesthetic was assessed using methylene blue. Mean arterial blood pressure decreased more severely after neuraxial lidocaine in thoracic epidural (10 and 30 microl) compared to high-volume (30 microl anaesthesia animals. Determination of the sympathetic blockade by means of laser Doppler perfusion imaging was restricted to the paws due to a higher density of subcutaneous blood vessels as compared to the abdominal wall (mean +/- SD: 3.93 +/- 0.06 vs. 1.35 +/- 0.05/384 mm(2), p < 0.05). Only high-volume (30 microl) lumbar and thoracic epidural anaesthesia (10 and 30 microl) increased skin perfusion in both hind and front paws. This extensive sympathetic blockade was demonstrated to include splanchnic segments using thermography. Segmental spread of methylene blue did not closely correspond to laser Doppler findings and should be interpreted as minimum rather than exact epidural spread of local anaesthetic.     

Rekonstruktion der Orbita mit Polylaktat-Implantaten: tierexperimentelle Ergebnisse nach 12 Monaten und klinischer Ausblick

In früheren Versuchen am experimentellen Modell gro?er Orbitadefekte beim Schaf konnten wir zeigen, dass bei der Rekonstruktion mit biodegradierbaren Membranen ohne zus?tzliche stützende Knochentransplantate oder Titan-Miniplatten-Osteosynthesen die Heilung durch osteokonduktives Knochenwachstum entlang den Membranen am ehesten ungest?rt verlief. In der vorliegenden Arbeit wurden gleichartige Defekte einseitig mit einer 0,5 mm dicken mikropor?sen Poly (L/DL 80/20)Laktatmembran überbrückt, auf der Gegenseite erfolgte die Rekonstruktion mit 0,25 mm dicken Membranen und stabilen Stützelementen aus dem gleichen Polylaktat. Nach 12-monatiger Beobachtung bei 9 Schafen ergab sich radiologisch eine seitengleiche anatomische Rekonstruktion der Orbitae. Histologisch zeigten sich dagegen ausgepr?gte Fremdk?rperreaktionen um degradierende Polylaktatmassen, welche vor allem um die degradierenden Stützelemente stattfanden, jedoch auch entlang der Membranen h?ufiger nachweisbar waren, als in unserem früheren Versuch nach 4 Monaten. In keiner Orbita waren die Implantate nach 12 Monaten vollst?ndig degradiert. Für eine zukünftige klinische Anwendung bei der Orbitarekonstruktion haben mikropor?se Membranen aus Polylaktat ihr osteokonduktives Potenzial best?tigt. Von der Verwendung stabiler Elemente aus dem gleichen Material muss wegen der sp?t auftretenden, massiven Fremdk?rperreaktionen für die Orbitarekonstruktion abgesehen werden.      

Nephrogenic adenoma of the urinary bladder with concomitant multiple adenomatous polyps of the large bowel. An abortive form of Gardner's syndrome? (author's transl)]

For the first time, a nephrogenic adenoma of the urinary bladder coinciding with multiple adenomatous polyps of the large bowel, in a 64-year-old male, is reported. The relationship of these tumors at different sites to a known clinical systemic disease is questionable; they could conceivably be ascribed to an abortive form of Gardner's syndrome. On the basis of a case report, the essential aspects of the nephrogenic adenoma of the urinary bladder are reviewed and discussed.     

Acetylcholinesterase staining differentiates functionally distinct auditory pathways in the barn owl

The aim of this study was to examine how the functional specialization of the barn owl's auditory brainstem might correlate with histochemical compartmentalizaiton. The barn owl uses interaural intensity and time differences to encode, respectively, the vertical and azimuthal positions of sound sources in space. These two auditory cues are processed in parallel ascending pathways that separate from each other at the level of the cochlear nuclei. Sections through the auditory brainstem were stained for acetylcholinesterase (AChE) to examine whether nuclei that process different auditory cues stain differentially for this enzyme. Of the two cochlear nuclei, angularis showed more intense staining than nucleus magnocellularis. Nucleus angularis projects to all of the nuclei and subdivisions of nuclei that belong to the intensity processing pathway. Acetylcholinesterase stained all regions that contain terminal fields of nucleus angularis and thus provided discrimination between the time and intensity pathways. Moreover, staining patterns with acetylcholinesterase were complementary to those prevously reported with an anti-calbindin antibody, which stains terminal fields of nucleus laminaris, and thus stains all the nuclei and subdivisions of nuclei that belong to the time pathway. Some of the gross staining patterns observed with AChE were similar to those reported with antibodies to glutamate decarboxylase. However, AChE is a more convenient and definitive marker in discriminating between these pathways than is calbindin or glutamate decarboxylase. Acetylcholinesterase staining of the intensity pathway in the owl may be related to encoding of sound intensity by spike rate over large dynamic ranges. © 1993 Wiley-Liss, Inc.     

Adrenocorticotrope Wirkung eines natürlichen und synthetischen ACTH-Präparates mit Gelatinezusatz bei intramuskulärer Injektion

Zusammenfassung Es wurde die Wirksamkeit eines synthetischen und natürlichen ACTH-Präparates mit Zusatz von 15% Gelatine nach intramuskulärer Injektion geprüft. Als Parameter wurden Ausamß und Dauer des Anstiegs der 11-OHCS im Plasma während der ersten 2 Std sowie 4, 8 und 12 Std nach der ACTH-Injektion zugrunde gelegt. Ein durch Venenpunktion bedingter 11-OHCS-Anstieg (Spritzenstress) konnte vorher ausgeschlossen werden. Die Untersuchung erfolgte als doppelter Blindversuch an 12 Probanden in zwei Gruppen, wobei 6 Versuchspersonen zuerst das synthetische und nach 1 Woche das natürliche Präparat erhielten und den anderen 6 Probanden die Präparate in umgekehrter Reihenfolge verabreicht wurden.Innerhalb der ersten 2 Std sowie nach 4 Std bestand in der Wirksamkeit beider Präparate kein Unterschied. Nach 8 bzw. 12 Std besaß das natürliche ACTH gegenüber dem synthetischen einen deutlich stärkeren Effekt. Bei dem synthetischen Präparat konnte ein prolongierender Effekt des Gelatins eindeutig festgestellt werden. Es ist anzunehmen, daß durch den Gelatinezusatz auch bei dem natürlichen ACTH-Präparat eine prolongierende Wirkung erzielt wird. Trotz dieses Zusatzes blieben die bereits bekannten Wirkungsunterschiede zwischen dem natürlichen und synthetischen ACTH deutlich.

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Summary The effect of a synthetic and a natural ACTH-preparation, to which 15% gelatine had been added, was tested following intramuscular injektion, the extend and duration of the increase of 11-OHCS in the plasma during the first 2 hours and following 4, 8 and 12 hours being used as parameter. An increase attributable to venous puncture alone (injection stress) had been excluded. A group of 12 patients was subdivided, i.e. 6 of them firstly received the synthetic preparation and a week after the natural one, the remaining 6 subjects receiving the preparation vice versa (double-blind study).During the first 2 hours and again after 4 hours the effect was not found to differ. However, after 8 respectively 12 hours the natural ACTH clearly showed a better effect as compared with the synthetic preparation; the latter showing an obviously prolonged effect due to the addition of the gelatine. It may be assumed that by adding gelatine a prolonged effect can be reached also with the natural ACTH-preparation. Apart from this addition the known difference in effect of both preparations clearly remained.

     

EMPATH: a neural network that categorizes facial expressions

There are two competing theories of facial expression recognition. Some researchers have suggested that it is an example of "categorical perception." In this view, expression categories are considered to be discrete entities with sharp boundaries, and discrimination of nearby pairs of expressive faces is enhanced near those boundaries. Other researchers, however, suggest that facial expression perception is more graded and that facial expressions are best thought of as points in a continuous, low-dimensional space, where, for instance, "surprise" expressions lie between "happiness" and "fear" expressions due to their perceptual similarity. In this article, we show that a simple yet biologically plausible neural network model, trained to classify facial expressions into six basic emotions, predicts data used to support both of these theories. Without any parameter tuning, the model matches a variety of psychological data on categorization, similarity, reaction times, discrimination, and recognition difficulty, both qualitatively and quantitatively. We thus explain many of the seemingly complex psychological phenomena related to facial expression perception as natural consequences of the tasks' implementations in the brain.     

Chemo-immunoprevention in superficial bladder cancer

We performed chemoimmune prophylaxis in 130 patients with superficial urothelial transitional cell carcinoma of the bladder. Two weeks after complete TUR 700 mg Cyclophosphamide (CTX)/m2 were injected intravenously followed by 6 weekly intravesical instillations of 120 mg BCG/50 ml saline together with BCG skin scarifications two weeks later. After 5 years the calculated frequency of recurrence was 18% in the treated group compared with 54% in the untreated historical control group. In a sub-group of 48 patients with recurrent tumors the CTX/BCG treatment success was well documented by comparison of the tumor recurrences during the appropriate time intervals before and after chemoimmune prophylaxis. The progression rate of the disease was generally more favourable in patients treated by CTX/BCG. No significant side effects of this treatment were noticed.     

Evaluation der potenziellen Regeneratschädigung bei der Kallusumformung nach Distraktionsosteogenese der Mandibula

Background

Molding the regenerate created by distraction osteogenesis has clinically been shown to be an efficient lifeboat, good enough that for complex three-dimensional deformities final adjustments by molding the regenerate may be part of the treatment plan. The study assessed the limits of molding a regenerate, taking into consideration compressive and tensile forces acting simultaneously on the fresh callus.

Material and methods

Distraction osteogenesis was performed in 15 beagle mandibles using custom-made devices which allowed for lengthening as well as for angulation. After linear distraction of 10 mm, a defined 20° angulation was performed in one acute step. The position of the fulcrum of the device allowed the regenerate to be compressed and stretched simultaneously. The effects on bone healing were assessed after 6 or 13 weeks of consolidation and compared to a control group where only linear distraction was performed.

Results

Radiological and histological investigations demonstrated that no significant difference between the biological behavior of the compressed and the stretched zone of the regenerate could be found. However, there were signs, showing the more critical character of the stretched area. After 6 weeks of consolidation, some specimens revealed delayed ossification of the stretched zone. Under stable conditions, this delay was compensated after 13 weeks of consolidation and complete osseous healing occurred.

Conclusions

Under stable conditions, a fresh regenerate can be molded to a considerable extent without endangering osseous healing permanently. Nevertheless, tensile forces acting on the regenerate should be minimized to prevent damage to the new bone. This can be achieved by overdistraction prior to callus molding or by gradually changing the vector of distraction during the lengthening process.     

Preferring one taste over another without recognizing either

Stimuli can be discriminated without being consciously perceived and can be preferred without being remembered. Here we report a subject with a previously unknown dissociation of abilities: a strong behavioral preference for the taste of sugar over saline, despite a complete failure of recognition. The pattern of brain damage responsible for the dissociation suggests that reliable behavioral choice among tastes can occur in the absence of the gustatory cortex necessary for taste recognition.     

A neural basis for the retrieval of words for actions

Although much has been learned in recent years about the neural basis for retrieving words denoting concrete entities, the neural basis for retrieving words denoting actions remains poorly understood. We addressed this issue by testing two specific anatomical hypotheses. (1) Naming of actions depends not only on the classical implementation structures of the left frontal operculum, but also on mediational structures located in left premotor/prefrontal areas. (2) The neural systems subserving naming of actions and naming of concrete entities are segregated. The study used the lesion method and involved 75 subjects with focal, stable lesions in the left or right hemispheres, whose magnetic resonance data were analysed with a three-dimensional reconstruction method. The experimental tasks were standardised procedures for measuring action and object naming. The findings offered partial support for the hypotheses, in that: (1) lesions related to impaired action naming overlapped maximally in the left frontal operculum and in the underlying white matter and anterior insula; and (2) lesions of the left anterior temporal and inferotemporal regions, which produce impairments in naming of concrete entities, did not cause action naming deficits. A follow-up analysis indicated that action naming impairments, especially when they were disproportionate relative to concrete entity naming impairments, were not only associated with premotor/prefrontal lesions, but also with lesions of the left mesial occipital cortex and of the paraventricular white matter underneath the supramarginal and posterior temporal regions.