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SummaryEffect of triacylglycerols containing medium and long-chain fatty acids (TML) on body fat accumulation was studied in rats. Male Wistar rats were fed an experi mental diet containing 25% soybean oil or TML for 6 weeks. The food intake for 6 weeks did not significantly differ between the two diet groups. However, the perirenal and mesenteric adipose tissue weight and carcass fat content were significantly lower in the TML diet group than in the soybean oil diet group. The epididymal adipose tissue weight and liver triacyl glycerol content did not significantly differ between the two diet groups. The digestibility of dietary fat did not significantly differ between the two diet groups. These results suggest that an intake of TML decreases body fat accumulation compared to an intake of soybean oil in rats. Key Words body fat accumulation, triacylglycerols containing medium and long-chain fatty acids, dietary fat, transesterification, rats Medium-chain triacylglycerols (MCT) are edible oils that consist of C8 and Cl0 saturated fatty acids. MCT were introduced to clinical nutrition in the 1950s for dietary treatment of malabsorption syndromes caused by rapid absorption (1). MCT were metabolized differ ently from long-chain triacylglycerols (LCT). Quite a few animal experiment studies have provided evidence that MCT diets lead to less body fat deposition compared to LCT diets (2-7). These results suggest that substitu tion of MCT for LCT in dietary fat could reduce dietary obesity if energy intake remained constant (1). MCT may have such a strong point, but utilization of MCT as cooking oil is limited. MCT are not good for high-tem perature cooking because of the lower smoking temper ature.Triacylglycerols containing medium and long-chain fatty acids (TML) are lipids that contain medium and long-chain fatty acids in the same triacylglycerol, and are made by transesterification of MCT and LCT. The smoking temperature of TML is higher than physical mixtures of MCT and LCT. TML are superior for high temperature cooking to physical mixtures of MCT and LCT.From the 1980s, studies have dealt with the effect of dietary TML on safety and whole body lipid oxidation. TML were rapidly oxidized compared with LCT in post operative patients and were not associated with any side effects (8). Recently, we have demonstrated that total energy expenditure was higher after TML inges tion than after LCT ingestion in healthy young women (9).

Lipoblastoma is a distinct benign fatty tumor composed of adipocytes, lipoblasts, and primitive mesenchymal cells with a myxoid stroma. Lipoblastoma harbors characteristic fusion genes involving the PLAG1, resulting in aberrant expression of PLAG1. However, the nature of the primitive mesenchymal cells remains obscure. In our routine pathology practice, we noticed desmin-positive spindle mesenchymal cells in lipoblastomas, which is a hitherto poorly described phenomenon. Thus, we examined the expression of several myogenic markers including desmin in a variety of 95 mesenchymal tumors with fatty elements. Fourteen of the 15 lipoblastomas examined contained desmin-positive spindle cells, which also showed nuclear expression of PLAG1, whereas α-smooth muscle actin, muscle specific actin, h-caldesmon, and myogenin were negative. Some spindle cells in subsets of atypical lipomatous tumors/well differentiated liposarcomas (6/20), dedifferentiated liposarcomas (11/31) and pleomorphic liposarcomas (2/10) were positive for actins and/or desmin, supporting focal myofibroblastic or smooth muscle differentiation. The other tumors, including 11 myxoid/round cell liposarcomas, four spindle cell lipomas, and four lipofibromatoses, were negative for all of the myogenic markers assessed. The almost consistent desmin expression in spindle mesenchymal cells suggests a potential diagnostic utility of this marker and myofibroblastic phenotype of fractions in lipoblastoma cells.

Monoamine oxidase (MAO) is an FAD-containing mitochondrial outer-membrane protein which catalyzes the degradation of several neurotransmitters in the central nervous system. The two subtypes of MAO, MAOA and MAOB, have similar primary sequences but different substrate and inhibitor specificities. The structure of human MAOB has recently been determined, but the structure of MAOA remains unknown. To clarify the mechanisms underlying their unique substrate and inhibitor recognition and thereby facilitate the development of new specific inhibitors to treat MAO-related neurological disorders, rat MAOA was crystallized in a complex with the specific inhibitor clorgyline. Diffraction data were collected to 3.2 A resolution. The crystal belongs to the space group P4(3)2(1)2, with unit-cell parameters a = b = 158.2, c = 258.4 A.