[Pelvic ring injuries]

PURPOSE

Analysis of the trauma patient of fractures of the pelvic ring and classification according to AO/Tile.

METHODS

125 unselected patients (43 females, 82 males) were evaluated retrospectively by conventional x-ray, and CT examinations included follow-studies.

RESULTS

Type-A fractures were seen in 36 (29%), Type-B fractures in 58 (46%), and Type-C fractures in 31 (25%) cases. Type-B and Type-C fractures mainly occurred in patients with traffic accidents and falls from great height. Type-A fractures were seen most often in patients with accidents at home or at work. However, in patients with complex fractures a classification concerning Type-B or Type-C fractures was difficult.

SUMMARY

Based on CT criterias, in most patients a statement concerning the applied forces, the stability of the pelvic rim and the fracture type can be made.

[Euphoric effect of lidocaine]

A 42 year old drug addict reported on his experiences with intravenous application of scandicaine and lidocaine. Lidocaine led to short-lasting euphoria comparable with former cocaine-induced effects. Pharmacological hypothesis to explain these mental alterations are discussed.

Brain size and morphology in miniaturized plethodontid salamanders

In six miniaturized salamanders of the family Plethodontidae, including one of the smallest tetrapod vertebrates. Thorius pennatulus, the anatomical consequences of miniaturization for the brain were investigated. We determined (1) absolute and relative size of the brain, major parts of the brain, the tectum and tectal gray matter, (2) nerve cell size and density, and (3) the number of cells within the visual and visuomotor centers (thalamus, tectum/praetectum and tegmentum). No common compensatory strategy for the brain among the miniaturized salamanders was found. Except for the smallest species, T. pennatulus, only some of the expected compensatory processes (increase in relative size of the brain, relative size of visual centers, relative amount of gray matter or relative density of cell packing density) are found in any species, and these occur in different combinations and degrees. The most decisive factor for maximizing cell number was cell size. Miniaturized species with small cells also have many visual cells, regardless of the other factors. In contrast, the minimum number of visual neurons is found in miniaturized salamanders with large cells. It is concluded that the neuroanatomical traits investigated exert different degrees of resistance to adaptive compensatory processes. Cell size seems to be the most resistant parameter and is strictly dependent on genome size.

Cell size predicts morphological complexity in the brains of frogs and salamanders

The morphological organization of the brain of frogs and salamanders varies greatly in the degree to which it is subdivided and differentiated. Members of these taxa are visually oriented predators, but the morphological complexity of the visual centers in the brain varies interspecifically. We give evidence that the morphological complexity of the amphibian tectum mesencephali, the main visual center, can be predicted from knowledge of cell size, which varies greatly among these taxa. Further, cell size is highly correlated with genome size. Frogs with small cells have more complex morphologies of the tectum than do those with large cells independent of body and brain size. In contrast, in salamanders brain-body size relationships also are correlated with morphological complexity of the brain. Small salamanders with large cells have the simplest tecta, whereas large salamanders with small cells exhibit the most complex tectal morphologies. Increases in genome, and consequently cell size, are associated with a decrease in the differentiation rate of nervous tissue, which leads to the observed differences in brain morphology. On the basis of these findings we hypothesize that important features of the structure of the brain can arise independently of functional demands, from changes at a lower level of organismal organization--in this case increase in genome size, which induces simplification of brain morphology.

The influence of intravenous L-tryptophan on plasma melatonin and sleep in men

The sleep-inducing mechanisms of L-Tryptophan (L-Trp) are generally thought to be mediated by a central serotonergic activation. Evidence is presented that some effects of L-Trp on sleep may be mediated by melatonin, a Trp-metabolite with sedative properties. Trp effects on vigilance, sleep, and plasma-melatonin concentrations were measured after double-blind application of 0, 1, 3, and 5 g L-Trp in nine and five healthy probands during daytime and nighttime, respectively. A significant sleep-inducing effect was observed after L-Trp administration during daytime and nighttime. The infusions of L-Trp caused a massive elevation of plasma melatonin levels. This effect was significant both during the night and the day, indicating that the increment of circulating melatonin may be of extrapineal origin.