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The stability, activity, and specificity of a cytosolic phospholipase A1 from bovine testis depends on the composition of membrane lipids. Manipulating the composition of membrane lipids increased its affinity for phosphatidic acid.

Research was conducted to examine an affinity purification technique for diacylglycerol kinase 1 (DGK1) that was based on the enzyme's ability to bind selectively to unilamellar lipid vesicles containing DG. Results demonstrate that the affinity purification technique was fast and effective which led to high yields of active enzyme. Findings also indicate that the method could be useful in the purification of other soluble DGKs and proteins that bind DG.

Research was conducted to investigate the partial purification of a specific transacylase found in bovine testis membranes and its copurification with an acyltransferase. The enzyme's ability to catalyze acyl transfer reactions in competition assays was also examined. Results suggested a possible role of the transacylase-acyltransferase in vivo and indicated that the partially purified enzyme contained only one transacyclase and one acyltransferase.

Mono Q fast protein liquid chromatography, LPA hydrolysis assays and (32P)LPA synthesis reveal that the bovine testis encodes a soluble phospholipase A1 which selectively causes the hydrolysis of phosphatidic acid in Triton X-100 micelle assays. Phospholipase A1 also exhibits lysophospholipase properties with lysophosphatidic acid and has an optimal pH range of 7.5 to 8.5. Phospholipase A1 concentration is more than 10-fold high in mature bovine testis than in the testis of newborn calf and is not detectable in heart, spleen or liver, indicating that it modulates spermatogenesis.

Human blood-derived monocyteswere incubated with reconstituted low density lipoproteins (LDLs) to study the ability of LDLs to provide arachidonic acid for eicosanoid biosynthesis. LDL treatment resulted in the production of key products of the prostaglandin H (PGH) synthase pathway, with only small amounts of products of the 5- lipoxygenase pathway detected. The results suggest the preferential utilizationof arachidonic acid in the PGH pathway, leading to the production of prostacylin, thromboxane A2 and prostaglandin E2. Additional findings indicate that other eicosanoids are produced by another mechanism involving LDL cholesteryl esters.

Low-density lipoproteins (LDL) are well known for their role in the regulation of cholesterol within the body, and high levels of LDL cholesterol carry an increased risk for heart disease. However, LDLs also are involved in the synthesis and regulation of prostaglandins, which are important mediators of inflammation and immunological reactions. The body cannot manufacture prostaglandins without substances such as linoleic acid derived from the diet. Research has now shown that, not only do the LDLs carry the raw materials for prostaglandin synthesis, but they also play a role in the regulation of the process. The lipoproteins, which are laden with fatty raw materials, bind to cells via the LDL receptor. This molecule then initiates the uptake of the LDL and the fats into the cell. The presence of the raw material on the LDL stimulates the initiation of synthesis of prostaglandins in the presence of platelet-derived growth factor, a substance involved in wound healing. However, as the cell digests the LDL it has incorporated, fragments appear to inhibit PDH synthase, an important enzyme of prostaglandin synthesis. Therefore, the LDL and receptor complex play a role in both the stimulation and inhibition of prostaglandin synthesis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Dislocation of the hip is a well-described event that occurs in conjunction with highenergy trauma or postoperatively after total hip arthroplasty. Bigelow first described closed treatment of a dislocated hip in 1870, and in the last decade many reduction techniques have been proposed. In this article, we review all described techniques for the reduction of hip dislocation while focusing on physician safety. Furthermore, we introduce a modified technique for the reduction of posterior hip dislocation that allows the physician to adhere to the back safety principles set for by the Occupational Safety and Health Administration. [ABSTRACT FROM AUTHOR]