In situ measurement of superoxide and hydroxyl radicals by frequency mixing detection technique.

Frequency mixing magnetic detection (FMMD) was used to detect superoxide from hypoxanthine and xanthine reaction and to detect hydroxyl radical from the Fenton reaction. FMMD was also applied to measure the reactive oxygen species (ROS) level released from microglial cells. We could assess the formation and extinction of the free radicals without a spin trap reagent. The FMMD signal amplitude scaled with the concentration of the radicals. It was verified that no signals are obtained from the substrates and reagents. Based on the observations and on previous research, we suggest that the FMMD signals originate from superoxide and hydroxyl radicals, indicating that FMMD can be used to detect O-centered radicals. Subsequent analysis of free radicals generated from living microglial cells showed that there were significant differences between the activated microglial cells and resting ones. The results of this research are promising regarding the applications of FMMD for in situ measurement of free radicals from various sources, including the cell.

Analysis of beta amyloid peptides employing the small probe molecules.

We herein describe an analytical method employing a small molecule array for the characterization of similar proteins based on ligand binding. In this study, 2 different beta amyloids (Abeta(1-40) and (1-42)) were selected as the model compounds. Their primary structures are identical except for 2 additional C-terminal amino acids. However, many studies have observed different biological and chemical characteristics of these peptides. Thus, the ability to distinguish these 2 peptides is important in the diagnosis and development of treatments for related disorders such as Alzheimer's disease. However, strong non-specific binding is usually observed, even when specific antibodies for each peptide are employed. In this study, Abeta(1-40) and Abeta(1-42) peptides were immobilized on a typical 96-well microplate. Twenty different small probe molecules (modified amino acids conjugated with FITC) were applied to the peptides acting as the secondary antibodies and labeling compounds. The results show that specific binding patterns occurred according to Abeta type and the analysis of the patterns can be used to distinguish these 2 similar peptides.

Extra-articular pigmented villonodular synovitis of the subacromial space.

Pigmented villonodular synovitis (PVNS) is a rare, benign, proliferating disease affecting the synovium of joints, bursae, and tendon sheaths. The knee is the most common site of involvement and accounts for up to 80% of cases. Involvement of the shoulder is extremely rare. Only 1 case of involvement of the subacromial space has been reported worldwide. We report a case of localized extra-articular PVNS of the subacromial space that was satisfactorily treated with open excisional biopsy and subacromial bursectomy after diagnostic glenohumeral arthroscopy. We visualized the glenohumeral joint to rule out articular invasion and intra-articular pathology with an arthroscope, which revealed a highly vascular synovium protruding into the intra-articular area of the rotator interval, with no direct invasion by the extra-articular mass. An open excisional biopsy and subacromial bursectomy was performed. The disease has not recurred during an 18-month follow-up period. The clinical manifestation, treatment, and prognosis of extra-articular PVNS are poorly understood, but if the lesion is left untreated, it can invade the surrounding soft tissue and joint. Therefore, early diagnosis and treatment are important for the satisfactory management of PVNS.