In vitro toxicity assessment of three hydroxylated fullerenes in human skin cells.

Carbon fullerenes possess unique properties and their interactions with biomolecules have widespread applications. Functionalization of fullerenes with hydroxyl groups (fullerenols) can increase the solubility and potential for cellular interaction, but the health and safety effects of varying degrees of fullerene hydroxylation in biological systems is poorly understood. Existing reports regarding the toxicity and inflammatory potential of fullerenols give conflicting conclusions. To further elucidate the potential for toxicity of fullerenols, human epidermal keratinocytes (HEK) were exposed to fullerenols (low (C60(OH)20), medium (C60(OH)24), and high (C60(OH)32)) at concentrations ranging from 0.000544-42.5 µg/ml for 24 and 48 h. A statistically significant (p<0.05) decrease in viability with alamar Blue (aB) was noted only with C60(OH)32 at 42.5 µg/ml after 24 h. Nanoparticle (NP) controls showed minimal NP/assay interference of the three fullerenols with the aB viability assay. Normalized IL-8 concentration for C60(OH)20 was not significantly different from control, while C60(OH)24 and C60(OH)32 showed a significant decrease at 24 and 48 h. These results suggest that different hydroxylation of fullerenes caused no cytotoxicity or inflammation up to 8.55 µg/ml. These findings suggest that extrapolation across similar NP will be dependent upon surface chemistry and concentration which may affect the degree of agglomeration and thus biological effects.

The influence of enactment on short-term recognition.

In three experiments subjects worked on a short-term memory recognition task (Sternberg Paradigm) with verbs. In Experiment 1 nouns were used in addition. Half of the verbs were encoded by a verbal learning task (VT), and the other half by a subject-performed task (SPT). With SPTs, subjects were required to perform the actions denoted by the verbs during study. With SPT, in Experiment 1 each verb of the memory set was performed and in Experiments 2 and 3 only a single verb of each list was performed, making this item unique. All encoding conditions showed set-size effects which did not interact with the type of encoding. Even response times on the single performed item of the set showed set-size effects, comparable in size to the other conditions. SPT did not change the slope of the reaction-time function over set size, but when the whole list had been performed subjects reacted more slowly in the SPT condition than in the VT condition, whereas when a single item was performed this item was recognised faster than the non-performed items. We conclude (a) that SPT does not influence memory entries in verbal short-term memory, (b) that the set-size effect has its origin in the access to the memory entry of the target based on the surface information of the words, and (c) that the effect of having performed the item is effective after this access to memory.

[The place of magnetic resonance tomography in the diagnosis of diseases of the shoulder joint]. / Stellenwert der Magnetresonanztomographie in der Diagnostik von Schultergelenkerkrankungen.

In a prospective study 43 patients with shoulder pain were examined by sonography and MRI. The findings were controlled by plain radiography, arthrography, and CT arthrography. Joint effusions and humeral head defects were equally identified by MR and sonography. In the diagnosis of labrum lesions, rotator cuff lesions, subacromial spurs, and synovial inflammatory disease sonography was not as accurate as MR. A special MR scoring system improved the diagnosis of an impingement syndrome.