To contribute to physiology and pathophysiology of the glomerulus of human kidney, we have launched a proteomic study of human glomerulus, and compiled a profile of proteins expressed in the glomerulus of normal human kidney by two-dimensional gel electrophoresis (2-DE) and identification with matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and/or liquid chromatography-tandem mass spectrometry (LC-MS/MS). Kidney cortices with normal appearance were obtained from patients under surgical nephrectomy due to renal tumor, and glomeruli were highly purified by a standard sieving method followed by picking-up under a phase-contrast microscope. The glomerular proteins were separated by 2-DE with 24 cm immobilized pH gradient strips in the 3-10 range in the first dimension and 26 x 20 cm sodium dodecyl sulfate polyacrylamide electrophoresis gels of 12.5% in the second dimension. Gels were silver-stained, and valid spots were processed for identification through an integrated robotic system that consisted of a spot picker, an in-gel digester, and a MALDI-TOF MS and / or a LC-MS/MS. From 2-DE gel images of glomeruli of four subjects with no apparent pathologic manifestations, a synthetic gel image of normal glomerular proteins was created. The synthetic gel image contained 1713 valid spots, of which 1559 spots were commonly observed in the respective 2-DE gels. Among the 1559 spots, 347 protein spots, representing 212 proteins, have so far been identified, and used for the construction of an extensible markup language (XML)-based database. The database is deposited on a web site (http://www.sw.nec.co.jp/bio/rd/hgldb/index.html) in a form accessible to researchers to contribute to proteomic studies of human glomerulus in health and disease.

Event-related potentials (ERPs) during a visual oddball paradigm with button-pressing responses were recorded in 12 right-handed subjects from 32 scalp electrodes. The single equivalent current dipole (ECD) of the target C1 (weak occipito-parietal negativity from 30-80 ms) was consistently located at the primary visual cortex. From the 4-ECD localization of the target P1/N1 (temporally coincident frontal positivity and occipito-temporal negativity), it was suggested that this complex reflected activities from distributed sources along both dorsal occipito-parietal and ventral occipito-temporal areas. The stable multiple ECD solutions for the target P3b were chosen as those including the left primary motor and/or sensorimotor dipole and satisfying goodness-of-fit (GOF) of more than 98% and confidence limit (CL) of less than 1 mm. The obtained frontal dipoles were discussed in terms of visual working memory and sustained attention in reference to the previous PET, fMRI and MEG studies. The distributed multiple ECDs may suggest that P3 should be interpreted as being the embodiment of the cortico-limbic-thalamic network which involves Halgren and Marinkovic's emotional and behavioral model and Mesulam's attentional circuit.

The authors have developed a PC-based multichannel electroencephalogram (EEG) measurement and analysis system. This system enables us (1) to simultaneously record a maximum of 64 channels of EEG data, (2) to measure three-dimensional positions of the recording electrodes, (3) to rapidly and precisely localize equivalent current dipoles (ECDs) responsible for the EEG data, and (4) to superimpose the localization results on magnetic resonance images. A new neural network and numerical analysis (NNN) approach to ECD localization is described which integrates a feedforward artificial neural network (ANN) and a numerical optimization (Powell's hybrid) method. It was shown that the ANN method has the advantages of high-speed localization and noise robustness, because in this approach: (1) ECD parameters are immediately initialized from the recorded EEG data by the ANN and (2) ECD parameters are accurately refined by the hybrid method. Our multiple ECD localization method was applied to sensory evoked potentials and event-related potentials using the present system.

We have proposed an XML format, HUP-ML (Human Proteome Markup Language), for proteomics database to exchange proteome data among researchers and to accelerate their collaboration. HUP-ML data model is proteome-analysis-oriented so as to incorporate such information as sample source, details of sample preparation, 2-D gel electrophoresis images, spot identification, amino acid sequences, MS spectrum data, and so on. We have developed prototypes of HUP-ML Editor and web-based database system as a tool for creating HUP-ML documents and a platform for sharing HUP-ML documents, respectively.

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