Steady-state visual evoked potentials reveal frontally-mediated working memory activity in humans

Steady-state visual evoked potentials (SSVEPs) reflect power changes at the stimulus driving frequency and have been used to assess brain activity reflecting cognitive processing. Only one study has demonstrated SSVEP modulation associated with working memory (WM), and none have compared the spatial localization of SSVEP modulations during WM performance with other brain imaging methods. Here we examined WM-related activity recorded with dense-array SSVEPs, analyzed using low resolution electromagnetic tomography, and compared the results to our previous findings using functional magnetic resonance imaging (fMRI). WM was associated with increased SSVEP activity over the right dorsolateral prefrontal cortex, paralleling our previous fMRI findings. Frontal WM-related SSVEP power correlated selectively with task performance. These results demonstrate the utility of SSVEPs for studying representational aspects of cognition.     

Semiautomated Quantitation of Carotid Artery Stenosis in Gadolinium-Bolus Magnetic Resonance Angiography

Magnetic resonance angiography (MRA) has become the standard method for evaluation of carotid occlusive disease. Fast imaging methods combined with bolus intravenous injection of gadolinium contrast have improved the quality of these images. Nevertheless, the gold standard for evaluation was based on projection arterial angiography. The properties of these images are rather different. Whereas most previous evaluations of MRA have used visual assessment of images, we evaluate an algorithm in which a computer algorithm plays the primary role in defining arterial lumen margins, hence, disease. The accuracy of this semiautomated algorithm is shown to compare favorably with gold-standard arteriography in a series of 50 patients.     

Intracellular Abeta is increased by okadaic acid exposure in transfected neuronal and non-neuronal cell lines.

Intracellular Abeta was examined in both a neuronal cell line (B103) expressing human APP with Swedish mutation and a non-neuronal cell line (Chinese hamster ovary, CHO) expressing wild human APP. Exposure of the APP695sw-transfected B103 cells to okadaic acid for 3 h, Abeta immunostaining was enhanced, as demonstrated by two independent anti-Abeta antibodies. The confocal microscopic study revealed that the immunoreactivity of Abeta was mainly colocalized with a Golgi marker and partially with an ER marker. Quantitative analyses, using Abeta sandwich ELISA, showed significantly increased intracellular Abeta. False positive detection of Abeta by antibody cross-reaction with APP was ruled out by extracting the fraction with formic acid and making it alkaline before subjecting it to ELISA. This procedure resulted in a fraction that contained little APP. Using CHO cells, OA treatment was also shown to be effective in increasing Abeta, as demonstrated by Western blot. The increased full-length APP and decreased APPC99 were also observed. This is the first study to demonstrate that OA treatment significantly increases intracellular Abeta.     

Procedure for Fluorescent-Antibody Staining of Virus-Infected Cell Cultures in Plastic Plates

Acetone fixation and fluorescent-antibody staining of virus-infected cell cultures were performed in plastic plates. Proper addition of acetone as a fixative did not alter the plastic.     

Anatomic basis of venous drainage in donor flaps

Summary The venous architecture in donor flaps was observed in 17 fresh cadavers by injection of latex or ink into the vessels or by making corrosion-cast specimens. The pattern of the veins resembles that of the arteries, with the difference that there is another set of venous trunks which do not accompany the arteries. Because these trunks are of larger caliber, they are the main drainage route for flaps. There are three types of drainage based on the anatomical architecture: 1) the superficial trunk is the main drainage path; 2) the deep trunk is the main path; 3) both superficial and deep veins are involved. These morphological considerations are the basis for selection of veins for anastomosis in microsurgery. The axial veins in temporal, frontal and facial flaps on the dorsum of the hand and the foot usually loosely accompany the axial arteries. The characteristics of these vascular pedicules should be studied in transplant operation.

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Bases anatomiques du drainage veineux des lambeaux cutanés libres

Résumé Le drainage veineux des lambeaux cutanés libres a été étudié sur 17 cadavres frais par injection de latex ou d'encre dans les vaisseaux, ou en réalisant des moulages par injection-corrosion. La distribution des veines ressemble à celle des artères à la différence près qu'il existe des troncs veineux qui n'accompagnent pas les artères. Ces troncs ont un calibre plus important et représentent une voie de drainage principale pour les lambeaux. On peut individualiser trois types de drainages basés sur l'architecture veineuse : 1. Le tronc superficiel est la principale voie de drainage ; 2. le tronc profond est la principale voie; 3. les veines superficielles et profondes sont impliquées simultanément. Ces considérations morphologiques sont les bases de la sélection des axes veineux pour les anastomoses en micro-chirurgie. Les veines axiales au niveau temporal, frontal et facial et pour les lambeaux de la face dorsale de la main et du pied sont habituellement relativement éloignées du trajet artériel. Les caractéristiques de ces pédicules veineux doivent être précisées pour la réalisation des lambeaux.

     

Facial expression recognition by people with mobius syndrome

We present an investigation of facial expression recognition by three people (BC, LP, and NC) with Mobius syndrome, a congenital disorder producing facial paralysis. The participants were asked to identify the emotion displayed in 10 examples of facial expressions associated with each of 6 basic emotions from the Ekman and Friesen (1976) series. None of the three people with Mobius syndrome was significantly impaired on this task. On a second test of facial expression recognition using computer-morphed facial expressions, NC showed a statistically significant impairment, BC a borderline deficit, and LP was unimpaired. However, even when impairments were found, people with Mobius syndrome still recognised many of the facial expressions shown to them. The recognition of facial expressions by people who have never been able to produce such signals on their own faces demonstrates that the ability to produce facial expressions is not a necessary prerequisite of their recognition.     

Immunoreactivity of a surface wall fraction produced by spherules of Coccidioides immitis.

The membranous spherule outer wall (SOW) isolated from liquid cultures of Coccidioides immitis has been shown to elicit reactivity with human anti-Coccidioides antibody by immunofluorescence and the immunodiffusion-tube precipitin assay. The serologically reactive components were extracted from SOW with the nonionic detergent N-octyl-beta-D-glucopyranoside (OG). The OG-soluble fraction of SOW was shown to be reactive with immunoglobulin G in 25 serum samples from coccidioidomycosis patients by an enzyme-linked immunosorbent assay. The isolated SOW and OG-soluble fraction of SOW were also demonstrated to be capable of eliciting lymphocyte blastogenesis. The antigenic and protein compositions of the OG-soluble fraction were examined by two-dimensional immunoelectrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively. Two antigens which were extracted from SOW were identified as antigens 2 and CS on the basis of the coccidioidin-anticoccidioidin reference system. The latter was isolated earlier and shown to correspond to a molecular mass (Mr) of 19 X 10(3) by SDS-PAGE under reducing conditions. This same electrophoresis band was shown to be reactive with sera from coccidioidomycosis patients by immunoblot analysis. One other SDS-PAGE component of the OG-soluble fraction of SOW with an Mr of 66 X 10(3) was shown to be reactive with sera from patients by immunoblot analysis. The SOW of C. immitis represents an important reservoir of immunoreactive wall components which has not previously been reported.     

Pseudomonas aeruginosa pyocyanin and 1-hydroxyphenazine inhibit fungal growth

AIM: To examine strains of Pseudomonas aeruginosa for specific antifungal factors. METHODS: Two clinical strains of P aeruginosa with strong in vitro inhibition (by cross streak assay) of Candida albicans and Aspergillus fumigatus were examined. Both strains were isolated from sputum--one from a patient with cystic fibrosis and one from a patient with bronchiectasis. Bacterial extracts were fractionated by high performance liquid chromatography and examined by ultraviolet absorbance and mass spectroscopy. Antifungal activity against C albicans and A fumigatus was determined in a well plate assay. RESULTS: Pyocyanin was the major antifungal agent of P aeruginosa; 1-hydroxy-phenazine also possessed activity. Pyocyanin MICs for C albicans and A fumigatus were > 64 micrograms/ml. These phenazines were active against nine other yeast species pathogenic for man. Preliminary experiments also suggested possible inhibition of yeast mycelial transformation in C albicans by pyocyanin. CONCLUSIONS: There may be a role for pyocyanin and 1-hydroxyphenazine in the prevention of pulmonary candidiasis in patients colonised by P aeruginosa.