The effect of medium and long chain triglyceride on human adipose tissue metabolism

Studies have been performed to assess the effects, in vivo and in vitro, of lipid emulsions on human adipose tissue prostaglandin production. Subcutaneous adipose tissue obtained either during elective surgery or by needle aspiration was studied in tissue culture or by using a perifusion apparatus. Physical mixtures of emulsions of long chain triglyceride (LCT) and/or medium chain triglyceride (MCT) were added to the tissue culture medium so that the final concentration was 400 mg/dl. After a 3-day incubation period the tissue was harvested, placed in buffer and used to determine in vitro production of prostaglandin E₂, prostacyclin I₂ (measured as its stable end product 6-keto PGF_1α) and thromboxane A₂ (measured as TXB₂) by radioimmunoassay. The results demonstrated that samples incubated in 100% MCT had the most significant increase in prostaglandin production, while those incubated in 100% LCT had the most significant decrease in activity of the three prostaglandins assayed. The addition of LCT to MCT caused a stepwise decrease in adipose tissue prostaglandin production. The data suggest a pharmacological rather than a physiological effect of lipid emulsions containing MCT and/or LCT on adipose tissue prostaglandin production. In vivo effects of a 20% safflower oil emulsion, containing high levels of the essential fatty acid linoleate, were assessed in five pediatric patients. Adipose tissue was obtained before and after two and four weeks of treatment. Fatty acid profiles and prostaglandin production were determined. The results demonstrated that intravenous fat infusion increased the concentrations of linoleic and arachidonic acids found in adipose tissue within a short interval. The effect of intravenous fat infusion on human adipose tissue prostaglandin production was less predictable and may have been a function of the patients' disease and subsequent clinical course. These findings suggest that lipid emulsions should not be viewed solely as a source of intravenous energy, because they may have the potential to elicit changes in prostaglandin production as demonstrated by a human adipose tissue model. Presented in part at the symposium on “Specialty Lipids and Their Biofunctionality,” at the annual meeting of the American Oil Chemists' Society, Philadelphia, May 1985.     

Laser-induced fluorescence detector for capillary-based isoelectric immunoblot assay

We describe a whole-capillary, multicolor laser-induced fluorescence scanner for microfluidic protein analysis systems. Separation of proteins is achieved by isoelectric focusing in a short length of fused-silica capillary after which the resolved proteins are immobilized to the capillary wall using photochemistry. The capillary is then evacuated, and fluorescently labeled antibodies are flowed through the capillary to bind to the immobilized proteins. This technique provides high sensitivity, the ability to spatially resolve and quantify proteins, and provides the opportunity for complete automation. Results obtained by fluorescence detection are compared to those obtained by chemiluminescence while offering enhanced resolution and signal stability.     

(Mis-) Direction of effect sizes.

Comments on an article by Dixon et al. (see record 2007-06671-001) regarding the effect sizes they presented in their meta-analysis of psychological interventions for arthritis pain management. The author of this comment claims that some of the individual effect sizes that they presented are erroneous and have therefore undermined their cumulative effect size estimates. After examining findings from other studies, he concludes that the Dixon et al. meta-analysis reports cumulative effect sizes (Hedge’s g) that overestimate the effects of psychological treatments upon arthritis pain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)