Secreted Phospholipase A2 Specificity on Natural Membrane Phospholipids.

The secreted phospholipase A2 (sPLA2) family contains 10 catalytically active isoforms. Current in vitro biochemical studies have shown that individual sPLA2s have distinct substrate selectivity in terms of the polar head groups or sn-2 fatty acids of their substrate phospholipids. Importantly, transgenic or knockout mice for distinct sPLA2s display nonoverlapping phenotypes, arguing that they do act on different phospholipid substrates and mobilize unique lipid metabolites in vivo. In an effort to comprehensively understand lipid metabolism driven by individual sPLA2s under pathophysiological conditions, we took advantages of mass spectrometric lipidomics technology to monitor the spatiotemporal changes in phospholipids (substrates) and products (fatty acids, lysophospholipids, and their metabolites) in tissues or cells of sPLA2-transgenic or knockout mice. The in vivo lipidomic data were compared with the in vitro activity of recombinant sPLA2s toward phospholipid mixtures extracted from the target tissues, cells, or extracellular membrane components on which sPLA2s may intrinsically act. These approaches reveal that the overall tendency in in vitro assays using natural membranes is recapitulated in several in vivo systems, often with even more selective patterns of hydrolysis. In this chapter, we will summarize current understanding of the in vivo substrate specificity of sPLA2s toward natural membrane phospholipids.

The Roles of the Secreted Phospholipase A2 Gene Family in Immunology.

Within the phospholipase A2 (PLA2) family that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, secreted PLA2 (sPLA2) enzymes comprise the largest group containing 11 isoforms in mammals. Individual sPLA2s exhibit unique tissue or cellular distributions and enzymatic properties, suggesting their distinct biological roles. Although PLA2 enzymes, particularly cytosolic PLA2 (cPLA2α), have long been implicated in inflammation by driving arachidonic acid metabolism, the precise biological roles of sPLA2s have remained a mystery over the last few decades. Recent studies employing mice gene-manipulated for individual sPLA2s, in combination with mass spectrometric lipidomics to identify their target substrates and products in vivo, have revealed their roles in diverse biological events, including immunity and associated disorders, through lipid mediator-dependent or -independent processes in given microenvironments. In this review, we summarize our current knowledge of the roles of sPLA2s in various immune responses and associated diseases.

Double sentinel lymph node mapping with indocyanine green and 99m-technetium-tin colloid in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) frequently metastasizes to cervical lymph nodes, which is the most known prognostic factor. Screening methods to identify sentinel lymph nodes (SLNs) are therefore of great interest for the management of potential neck metastasis. The purpose of this study was to evaluate the clinical benefit of double SLN mapping with indocyanine green (ICG) and 99m-technetium-tin colloid ((99m)Tc-tin colloid) for sentinel node navigation surgery (SNNS). Between 2007 and 2010, 16 patients diagnosed with OSCC were investigated by SLN biopsy using the double mapping method. (99m)Tc-tin colloid was injected into the peri-tumoural region on the preoperative day, and ICG was administered intraoperatively in the same position to assist in detecting nodes during surgery. Based on the gamma-ray signal and near-infrared (NIR) fluorescence of ICG, SLNs were identified and thereafter assessed pathologically and genetically for cancer involvement. Radio-guided detection was successful for all patients. ICG mapping identified a relatively larger number of nodes, suggesting that several non-SLNs were potentially involved. The double mapping method assisted surgeons to explore SLNs. Since the ICG fluorescence was shielded by the subcutaneous fatty tissue and the muscle layer including platysma and sternocleidomastoid, it was necessary to retract the tissue away from nodes.

Response of diffuse sclerosing osteomyelitis of the mandible to alendronate: follow-up study by 99mTc scintigraphy.

We report a case of diffuse sclerosing osteomyelitis of the mandible responded to alendronate, after a poor response to intravenous antibiotics, antibiotic irrigation-perfusion, and decortication. The patient was given an intravenous infusion of 10mg of alendronate. Pain resolved within 24 h. There were no severe adverse events. Increased uptake of 99mTc in the mandible almost completely disappeared 3 months after treatment.

Rapid adsorption pretreatment with submicrometre powdered activated carbon particles before microfiltration.

Manufacturer-supplied powdered activated carbon (PAC) was ground to produce submicrometre particles (0.8 and 0.6 m median diameter) for use as an adsorbent before microfiltration (MF) for drinking water treatment. Batch tests revealed that the microground PAC adsorbed natural organic matter (NOM) much more rapidly and had a higher adsorptive capacity than ordinary PAC. The water samples pretreated with the submicrometre PAC were subjected to MF, and the results of experiments with different PAC contact times revealed that a 1 min retention time was sufficient for adsorptive removal of NOM. The use of submicrometre PAC permitted not only shorter PAC contact times but also a 75% reduction in dose.