Effect of dietary alpha-linolenic acid and its ratio to linoleic acid on platelet and plasma fatty acids and thrombogenesis

The effect of dietary alpha-linolenic acid (18:3n-3) and its ratio to linoleic acid (18:2n-6) on platelet and plasma phospholipid (PL) fatty acid patterns and prostanoid production were studied in normolipidemic men. The study consisted of two 42-d phases. Each was divided into a 6-d pre-experimental period, during which a mixed fat diet was fed, and two-18 d experimental periods, during which a mixture of sunflower and olive oil [low 18:3n-3 content, high 18:2/18:3 ratio (LO-HI diet)], soybean oil (intermediate 18:3n-3 content, intermediate 18:2/18:3 ratio), canola oil (intermediate 18:3n-3 content, low 18:2/18:3 ratio) and a mixture of sunflower, olive and flax oil [high 18:3n-3 content, low 18:2/18:3 ratio (HI-LO diet)] provided 77% of the fat (26% of the energy) in the diet. The 18:3n-3 content and the 18:2/18:3 ratio of the experimental diets were: 0.8%, 27.4; 6.5%, 6.9; 6.6%, 3.0; and 13.4%, 2.7, respectively. There were appreciable differences in the fatty acid composition of platelet and plasma PLs. Nevertheless, 18:1n-9, 18:2n-6 and 18:3n-3 levels in PL reflected the fatty acid composition of the diets, although very little 18:3n-3 was incorporated into PL. Both the level of 18:3n-3 in the diet and the 18:2/18:3 ratio were important in influencing the levels of longer chain n-3 fatty acid, especially 20:5n-3, in platelet and plasma PL. Production of 6-keto-PGF1 alpha was significantly (P < 0.05) higher following the HI-LO diet than the LO-HI diet although dietary fat source had no effect on bleeding time or thromboxane B2 production.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison between Walsh and Fourier analysis of the electroencephalogram for tracking the effects of anesthesia

The effects that anesthesia has on the surgical patient can be characterized with the electroencephalogram (EEG). These effects are typically quantified through frequency analysis of the EEG signal. The fast Fourier transform (FFT) is usually employed for this purpose. In recent years, the fast Walsh transform (FWT) has been proposed as an alternative to the FFT for signal analysis because it is computationally more efficient, requiring less time to complete on a digital computer. This paper statistically evaluates the quantitative and dynamic differences between the results of Walsh and Fourier analysis of the EEG done for the purpose of characterizing the effects of anesthesia. This paper shows that there are quantitative differences between the results of the two frequency analysis techniques but they are dynamically equivalent, both showing essentially the same changes due to the effects of anesthesia. The efficiency of the FWT has been reconfirmed. These results support the use of the FWT in place of the FFT for tracking the effects of anesthesia on surgical patients with the EEG.